Sound Localization for an Electronic Call

ABSTRACT

A smartphone provides a voice of a person during a telephone call to a user of the smartphone in binaural sound. The smartphone stores HRTFs of the user, and a digital signal processor (DSP) processes the voice of the person with the HRTFs so the voice of the person externally localizes in the binaural sound at a sound localization point (SLP) that is in empty space one meter away from a head of the user.

BACKGROUND

Electronic devices typically provide monophonic or stereophonic sound tousers. This sound has good speech intelligibility but is not equivalentto sound that the listeners would hear if they were proximate to asource of the sound. During a telephone call for example, listeners hearsound through a speaker in the electronic device or through headphonesattached to the electronic device. This sound is not comparable inquality to sound that the listeners would hear if they werecommunicating face-to-face with each other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a method to provide sound that is localized at a soundlocalization point in accordance with an example embodiment.

FIG. 2 is a method to adjust sound as a listener moves with respect to asound localization point in accordance with an example embodiment.

FIG. 3 is a method to adjust sound in an electronic call in response toa listener moving a location and a head orientation with respect to asound localization point in accordance with an example embodiment.

FIG. 4 is a method to adjust sound that a listener hears as a talkermoves with respect to a virtual microphone point in accordance with anexample embodiment.

FIG. 5 is a method to adjust sound that a listener hears as a talkermoves with respect to a virtual microphone point during an electroniccall between the talker and the listener in accordance with an exampleembodiment.

FIG. 6 is a method to designate sound localization points forindividuals during an electronic call in accordance with an exampleembodiment.

FIG. 7 is a method to adjust sound based on a physical environment of anindividual in accordance with an example embodiment.

FIG. 8 is a method to adjust sound based on an artificial environment inaccordance with an example embodiment.

FIG. 9 is a method to adjust HRTFs of an individual during an electroniccall in accordance with an example embodiment.

FIG. 10 is a method to execute recorded sound at a sound localizationpoint in accordance with an example embodiment.

FIG. 11 is a method to select HRTFs for a listener in accordance with anexample embodiment.

FIG. 12 is a method to calculate HRIRs for a listener in accordance withan example embodiment.

FIG. 13A shows a sound source providing a sound wave to a listenerfacing the sound source in accordance with an example embodiment.

FIG. 13B is a graph of a sound wave arriving at the listener in FIG. 13Ain accordance with an example embodiment.

FIG. 13C shows the sound source providing a sound wave to the listenerfacing away at ninety degrees (90°) from the sound source in accordancewith an example embodiment.

FIG. 13D is a graph of a sound wave arriving at the listener in FIG. 13Cin accordance with an example embodiment.

FIG. 14 is a graph of ITDs for various head orientations with respect toa propagation direction of the sound wave in accordance with an exampleembodiment.

FIG. 15 is a graph of ILDs for various sample frequencies across headorientations from 0° to 180° with respect to a propagation direction ofa sound wave in accordance with an example embodiment.

FIG. 16 is an electronic system that includes users and electronicdevices at different geographical locations in accordance with anexample embodiment.

FIG. 17 is an electronic system that includes a listener wearing awearable electronic device in accordance with an example embodiment.

FIG. 18 is an electronic system in which electronic devices of twoindividuals communicate during an electronic call in accordance with anexample embodiment.

FIG. 19 is an electronic system that includes a wearable electronicdevice of an individual in accordance with an example embodiment.

FIG. 20 is an electronic system in which electronic devices of twoindividuals communicate during an electronic call in accordance with anexample embodiment.

FIG. 21 is an electronic system in which electronic devices of twoindividuals communicate during an electronic call in accordance with anexample embodiment.

FIG. 22 is an electronic system in which electronic devices of twoindividuals communicate during an electronic call in accordance with anexample embodiment.

FIG. 23 is an electronic system in which electronic devices of multipleindividuals communicate during an electronic call in accordance with anexample embodiment.

FIG. 24 is another electronic system in which electronic devices of twoindividuals communicate during an electronic call in accordance with anexample embodiment.

FIG. 25 is another electronic system in which electronic devices of twoindividuals communicate during an electronic call in accordance with anexample embodiment.

FIG. 26 is an electronic system that includes multiple electronicdevices and storage in communication with each other in accordance withan example embodiment.

SUMMARY OF THE INVENTION

One example embodiment is a computer system in which two electronicdevices communicate with each other during a telephone call between twopeople. The computer system positions a voice of one person at a soundlocalization point that is proximate to the other person.

DETAILED DESCRIPTION

Example embodiments include systems, apparatus, and methods that providea sound localization point (SLP) to a listener.

In order to determine a location of sound, humans process and comparemonaural cues from each ear. This comparison reveals difference cues orbinaural cues that enable sound localization. These cues includeinteraural time differences (ITDs), interaural level differences (ILDs),and head-related transfer functions (HRTFs). Cues thus result fromchanges to the sound wave from an interaction with the human anatomy.Humans process these changes as impulse responses or head-relatedimpulse responses (HRIRs). Once the HRIRs for an individual are known,the associated or transformed HRTFs can be calculated. The HRIRs andtransformed HRTFs enable sound to be convolved such that a location ofthe sound or sound localization point can be changed. A listener hearsthe convolved sound as if it had originated from the sound localizationpoint.

FIG. 1 is a method to provide sound that is localized at a soundlocalization point.

Block 100 states capture sound that will be provided to a listener.

Different types of sound (such as monophonic, stereophonic, and binauralsound) can be received, recorded, stored, augmented, generated,processed, and/or transmitted. This sound can be provided in real-timeto a listener, processed and delayed, or stored in memory. Examples ofcapturing sound include, but are not limited to, A-B technique or TimeDifference Stereo (e.g., using two spaced apart omnidirectionalmicrophones to record audio signals), X-Y technique or IntensityStereophony (e.g., using two microphones at a same location and pointedat different angles), Mid/Side Stereophony (e.g., using twobidirectional microphones facing different directions), Near-Coincidenttechnique (e.g., combining principles of the A-B technique, the X-Ytechnique, or other techniques), processing monophonic sound (e.g.,processing recorded monophonic sound to create an impression of stereosound), spaced microphones on a dummy or model human head (e.g., placingmicrophones in an eardrum or at the ear of an artificial head or aprinted 3D head), spaced microphones on a real human head (e.g., placingmicrophones in eardrum or at the ear of the human head), spacedmicrophones on a stationary or moving object such as a purse, a human,an electronic device, a motorized vehicle, a bicycle, etc., augmentedstereo (e.g., recording stereo sound and processing it to imprinthead-related transfer functions (HRTFs) to produce binaural sound), atechnique that uses one or more microphones (e.g., spacing microphonesto capture sound), or generated sound with a computer.

Block 110 states designate a sound localization point at a location inempty space that is away from and proximate to a location of thelistener such that the sound localization point simulates an origin ofthe sound that the listener hears.

A listener of the detected sound can localize the sound to determine adistance and a direction of the sound. For example, a listener of adetected sound perceives a point or an area (i.e., a sound localizationpoint) from where the sound emanates or originates. For captured soundreplayed electronically, this perceived sound localization point is ator near the device emitting the sound, such as an electronic speaker.Example embodiments can modify or move the sound localization point to alocation that is apart from and away from the device emitting the sound.A sound localization point can exist in a three-dimensional (3D)position described by an azimuth or horizontal angle, elevation orvertical angle, and distance from the listener for static sounds orvelocity with respect to the listener for moving sounds. A soundlocalization point can also exist in a two-dimensional (2D) positiondescribed by an azimuth or horizontal angle and distance from thelistener for static sounds or velocity with respect to the listener formoving sounds.

For example, if a position and a shape of the ears of a listener areknown or estimated to a suitable degree of accuracy, binaural sounddelivered to this listener can be altered in order to create, move,and/or adjust the sound localization point. A location of sound and/or adirection to the sound can be altered or created using one or more ofhead-related transfer functions (HRTFs), accounting for differences inarrival times between the ears (interaural time differences),differences in amplitude or level of the sound between the ears(interaural level differences), asymmetrical spectral reflections fromparts of the body (such as torso, shoulders, and pinnae), phase delays,group delays, and a ratio of the direct signal to the reverberatedsignal.

A computer, electronic device, or a person can designate the soundlocalization point. For example, a listener may set a sound localizationpoint to follow him as he moves, remaining at a fixed point in his frameof reference, adjacent to or near himself, such as a point three feet tohis left at the height of his own head. As another example, a computerprogram may set a sound localization point at a static geographiclocation such as a predetermined Global Positioning System (GPS)location or a specific location in a room or building. As anotherexample, a speaking person could set the sound localization of histransmitted voice to a point within the reference frame of the listener,six inches from the face of the listener. As another example, anelectronic device such as a tablet may set the default soundlocalization of music it is playing to a point one foot directly abovewhere it lays flat on a desk.

Block 120 states adjust the sound so the sound originates from the soundlocalization point at the location in empty space that is away from andproximate to the location of the listener.

Adjustments to the sound are made so the sound emanates or originatesfrom the sound localization point. For example, the sound is processedso sound localization occurs for the listener to emanate from ororiginate at the sound localization point. For instance, the sound isprocessed to alter, add, or generate head-related transfer functions(HRTFs), interaural time differences, and/or interaural leveldifferences to correspond to a fixed or variable distance from thelistener, a coordinate location or a GPS location of the soundlocalization point.

Block 130 states provide the sound to the listener such that thelistener localizes the origin of the sound at the sound localizationpoint in empty space.

The sound appears to emanate from or originate from the soundlocalization point that is away from the listener. The origin of thissound can be a location in empty space, such as a place where nophysical object exists or a location where a physical object exists.Further yet, an origin of this sound from the point-of-view of thelistener can be proximate to the listener (such as in a same room) orfar away from the listener (such as several kilometers away).

A sound localization point (SLP) or a virtual microphone point (VMP) canbe designated to an empty space, an occupied space, or an availablespace. For example, an available space is an empty space that is alsounoccupied by a SLP, VMP, virtual object, or other manifestation orrepresentation of a remote real or virtual character or object. Anindividual may also designate in accordance with these embodiments anon-empty or a non-available space as a SLP and/or VMP. For example alistener designates a chair as SLP for a remote speaking person, and thechair is occupied by a doll or pet dog in which case the listener wouldperceive the voice of the remote speaking person as emanating from thedoll or dog. In another example where a listener is conversing with twoother people on a conference call, the listener designates the SLP ofboth voices at the same cigar box laying on the conference table, andthe VMP of both voices also at the point of the cigar box. Thesedesignations create a perception for the listener that both voices areemanating from the same cigar box, and both are listening from the samecigar box.

In an example embodiment, a distance from the sound localization pointto the listener is different than a distance from an origin of the soundto the microphones that captured the sound. Furthermore, a horizontalangle and/or a vertical angle from the sound localization point to thelistener are different than a horizontal angle and a vertical angle fromthe origin of the sound to the microphones. For example in a Cartesiancoordinate system, a microphone is located at (0, 0, 0) with an originof sound located at (5, 9, 15). The sound is adjusted to change one ormore of the (X, Y, Z) coordinates. For instance, when a listener islocated at (0, 0, 0), an origin of the sound or the sound localizationpoint for the listener appears to originate from (10, 17, 25). Asanother example, microphones are located in earpieces of a talkingperson. A listening person wears earpieces with speakers in each ear andhears a voice of the talking person originating from a point that is tenfeet to one side of the listening person at a height equal to a heightof the listening person.

The coordinates and/or locations of multiple different sounds cansimultaneously be changed. For example, microphones capture sound fromtwo different speaking people and from a background noise source.Locations of the speaking people with respect to the microphones arealtered, and the background noise is filtered.

Consider an example in which binaural sound of a bird chirping isrecorded while microphones are two feet away from and at a same heightof the bird. A listener of this recording would localize the bird to betwo feet away since the microphones were two feet away from the realbird at the time of the recording. The sound localization point (i.e.,two feet away from the listener) is changed to generate a differentsound localization point. For example, the binaural sound is processedto change the sound localization point from being two feet away from thelistener to being thirty feet away from the listener. In this example,moving the sound localization point includes changing one or more oflocalization of a vertical elevation of the sound, a horizontalelevation of the sound, and a distance to an origin of the sound.

Consider an example in which a listener sits at his kitchen table andhas an electronic telephone call with his mother. Both the listener andthe mother wear electronic devices in or near their ears that capture,transmit, and provide sound for the telephone call. These electronicdevices record binaural sound of the speaker and provide binaural soundto the listener. The listener designates an empty kitchen chair next tohim as a sound localization point for the voice of his mother. Duringthe telephone call, the voice of the mother appears to originate fromthe empty kitchen chair such that the listener localizes her voice tothis location. From the point of view of the listener, the telephoneconversation sounds like the mother is sitting in the kitchen chair andtalking to the listener.

FIG. 2 is a method to adjust sound as a listener moves with respect to asound localization point.

Block 200 states designate for a listener a sound localization point inempty space that simulates a location of a source of sound that thelistener hears such that the sound localization point is away from andproximate to the listener.

A person or an electronic device designates the location of the soundlocalization point. For example, the listener of the sound, a speaker ofthe sound, or a computer that transmits, processes, stores, and/orprovides the sound designates where an origin of the sound will occur.This location for the origin of the sound can be different from alocalization point when the sound was recorded or captured.

Consider an example in which two spaced apart microphones recordbinaural sound. These microphones are stationary in a room and recordthe following sounds that occur in the room: footsteps at a firstcoordinate (a first vertical angle, a first horizontal angle, and afirst distance), a voice of a person talking at a second coordinate (asecond vertical angle, a second horizontal angle, and a seconddistance), and a sound of an opening door at a third coordinate (a thirdvertical angle, a third horizontal angle, and a third distance). Thebinaural recordings of the three sounds (i.e., footsteps, voice, andopening door) can be stored to preserve their original soundlocalization points. As such, a listener of the recording would hear thefootsteps at the first coordinate, the voice at the second coordinate,and the opening door at the third coordinate. Alternatively, thebinaural recordings of these three sounds can be altered to change theirrespective sound localization points to new or different soundlocalization points. As such, a listener of the altered recording wouldhear the footsteps at a fourth coordinate different than the firstcoordinate, the voice at a fifth coordinate different than the secondcoordinate, and the opening door at a sixth coordinate different thanthe third coordinate.

Block 210 states determine a location and a head orientation of thelistener with respect to the sound localization point in empty space.

The sound localization point can represent an origin of a sound, such asa voice of a person. The sound appears to emanate from the soundlocalization point as if the person were located at this point andspeaking.

The listener has a head orientation and a location with respect to thissound localization point. For example, a head orientation of thelistener could be directed at, toward, or away from the soundlocalization point. A location of the listener could be at, next to,near, or far from the sound localization point. The location and headorientation can be given as distances and angles, such as being at anX-Y-Z coordinate or being ten degrees (10°) azimuth, twenty-five degrees(25°) elevation, and six (6) feet.

Measurements can be made of the location and the head orientation of thelistener with respect to the sound localization point. By way ofexample, these measurements can be made with one or more electronicdevices with facial recognition, a motion capture system, a gazetracker, a GPS locator, a system tracking angular head velocity and/oracceleration, a camera (including a camera in a computer or an augmentedor virtual reality application), a tag (such as a radio, radio frequencyidentification (RFID), or GPS tag system), binaural headsets or earpieces (for example sensing interaural level differences and/orinteraural time differences), a laser, a sensor (such as a sensorlocated in a smartphone on which a person speaking), a gyroscope, amagnetometer, and an accelerometer. For instance, a head orientationtracker measures one or more rotational head orientations of yaw(side-to-side or left and right), pitch (up and down), and roll(tilting) of the head.

Block 220 states adjust the sound as the listener moves with respect tothe sound localization point in empty space such that the location ofthe source of the sound that the listener hears continues to emanatefrom or originate from the sound localization point even as the listenermoves and changes the location and the head orientation with respect tothe sound localization point.

Measurements for the head orientation and location of the listener canoccur in real-time, such as being measured continuously, continually,periodically, in response to motion, or in response to an action orevent. As the listener moves a head orientation and/or a location withrespect to the sound localization point, the sound continues to appearto emanate or originate from the sound localization point. For example,adjustments are made to amplitude of the sound, interaural timedifferences, interaural level differences, and head-related transferfunctions (HRTFs). These adjustments are made in real-time as thelistener moves.

Consider an example in which sound of an artificial or imaginary birdsinging is localized to a real tree in a park. A listener wears anearpiece that communicates with an electronic system that providesbinaural sound recordings of the bird to the listener. The electronicsystem tracks a location and a head orientation of the listener withrespect to the tree. Assume the listener is standing in the park suchthat the listener hears the sound of the bird singing up in the treethat is located behind the listener. The singing of the bird thusappears to emanate from the tree that is behind the listener. As thelistener turns around to face the tree, adjustments are made to thebinaural sound such that the singing appears to emanate in the tree andin front of the listener. As the listener walks toward the tree,amplitude of the singing increases (i.e., the sound gets louder) sincethe listener is moving closer to the sound localization point of thebird singing in the tree. If the listener walked to a location under thetree, then the singing of the bird would appear to be directly above thelistener.

Consider an example in which a listener has a video call with a friendon a notebook computer. An image or video of the friend appears on adisplay of the notebook computer, and the listener wears earphones thatprovide binaural sound to the listener. The notebook computer tracks aposition of the listener as he moves with respect to the notebookcomputer. Variations in the binaural sound emulate variations as if thenotebook computer were the head of the friend such that the listenerlocalizes sound to the notebook computer that is a sound localizationpoint. In other words, from a pure audial point-of-view, the listenerhears his friend as if his friend were situated at the location of thenotebook computer. Adjustments are made to the interaural timedifferences, interaural level differences, and HRTFs as the listenermoves his body and head with respect to the location of the notebookcomputer.

Consider an example in which voices of participants in an electronicconference call are localized to specific points or areas in spacearound one or more participants. Sound is then adjusted based on headorientation and/or location of the participants. Talking with a personover an electronic device more closely emulates talking with the personas if both parties were talking directly to each other.

During a communication between two or more participants, binaural soundis adjusted in real time in response to movements of the participants inorder to emulate the experience of talking face-to-face directly with ahuman. The sound that a listener hears also changes as the listenerchanges a distance to the sound localization point. For example, soundintensity decreases inversely proportional to a square of the distancefrom a measuring point (e.g., an ear of a listener) to an origin of thesound. Sound that a listener hears also changes as the head orientationof the listener changes with respect to the origin of the sound, such asmoving the head left-right, up-down, or in a tilting motion. Forexample, the interaural time difference changes as the listener moveshis head and changes an angle with respect to the sound source, such aschanging from a 0 degree azimuth to a 180 degree azimuth.

Consider a first scenario in which John and Paul are talking as they sittwelve feet apart in an apartment room. During the conversation, Johnstands from his chair, walks to the refrigerator, opens a can of soda,and returns to his chair. Paul remains in his chair as John walks to therefrigerator. Paul hears John since both individuals are located in theroom together.

Consider a second scenario in which Paul travels to another country, andJohn initiates a video call with Paul. John sits in his chair and hisnotebook computer rests in Paul's chair that is twelve feet away (i.e.,the same chair where Paul sat in the first scenario). John and Paul havethe same conversation as in the first scenario, and John performs thesame actions (i.e., during the conversation, John stands from his chair,walks to the refrigerator, opens a can of soda, and returns to hischair). In this second scenario, the notebook computer provides Paul'svoice in stereo sound. John does not hear or perceive Paul's voice inthe same manner as the first scenario since the notebook computerprovides Paul's voice in stereo sound.

Consider a third scenario in which Paul travels to another country andinitiates a call with John. John and Paul both wear electronic earpiecesthat record and provide binaural sound. When the call initiates, thevoice of Paul is localized to his empty chair in John's apartment whileJohn sits in his chair. John and Paul have the same conversation as inthe first scenario, and John performs the same actions (i.e., during theconversation, John stands from his chair, walks to the refrigerator,opens a can of soda, and returns to his chair). In this third scenario,John hears and perceives Paul's voice in a same manner as in the firstscenario. In the first and third scenarios, Paul's voice had a samesound localization point for John even as John moved around the room. Inthe first and third scenarios, the sound intensity, the interaural timedifferences, the interaural level differences, and output from the HRTFschanged in real time as John stood from his chair, walked to therefrigerator, opened the can of soda, and returned to his chair. FromJohn's point-of-view, the first and third scenarios were audibly thesame since the sound that John heard in the third scenario copied oremulated the sound that John heard in the first scenario.

Consider a fourth scenario in which John specifies a sound localizationpoint in the apartment for Paul's voice on the occasion of each call,such as specifying a location on a couch or standing in a doorway.Alternatively, Paul's voice originates from a starting default soundlocalization point on the occasion of each call. For example, thisdefault sound localization point is three feet from John at a verticalheight equivalent to the vertical height of John's head.

Consider a fifth scenario that is similar to the third scenario. In thefifth scenario, however, the sound localization point of Paul changes ormoves during the conversation. Initially, Paul's voice is localized tohis chair. When John stands up and begins to walk toward therefrigerator, the sound localization point of Paul moves and followsJohn as if Paul were present in the apartment and moving with the soundlocalization point.

Consider an example in which a listener is located in a room withspeakers, and the listener does not wear headphones or an electronicdevice providing sound to the ears. The speakers provide binaural soundto the listener, and a crosstalk cancellation (CTC) system adjusts,removes, filters, or moves a crosstalk location in real-time as thelistener moves around the room. Multiple sound localization points existin the room, and binaural synthesis of sound dynamically occurs inreal-time as the listener moves his head and/or body. As the listenerwalks around the room, the sound localization points remain fixed orunmoved to provide virtual sound sources located in the room. If thevirtual sound source represents a fixed object, then the virtual soundsource remains fixed in the room. For instance, sound that emanates froma virtual water fountain is a fixed sound source since the virtual waterfountain does not move. If the virtual sound represents a moving object,then the virtual sound source moves in the room. For instance, soundthat emanates from a virtual bird can move since the bird can fly fromone location in the room to another location in the room and thus changeits sound localization point.

FIG. 3 is a method to adjust sound in an electronic call in response toa listener moving a location and a head orientation with respect to asound localization point.

Block 300 states commence an electronic call between a first individualand a second individual that are remote from each other.

The electronic call can be commenced with an electronic device thatincludes, but is not limited to, a smartphone, a computer (such as atablet computer, a notebook computer, a desktop computer, etc.), ahandheld portable electronic device (HPED), a wearable electronic device(such as electronic glasses, an electronic watch, an electronicearpiece, headphones, etc.), a telephone, a computer system, and anelectronic system.

The first and second individuals are acoustically remote from eachother, such as being in separate physical or computer-generated rooms,separate physical or virtual buildings, separate virtual realities oronline games or computer rendered chat or play spaces, different cities,different states, different countries, etc.

Block 310 states designate, for the first individual, a soundlocalization point that simulates a location in empty space from wherean origin of a voice of the second individual occurs for the firstindividual.

The sound localization point represents a location where the firstindividual localizes the voice of the second individual during theelectronic call. Even though the second individual is physically orvirtually remote from the first individual, the first individual canlocalize the voice of the second individual in a similar manner as ifthe second individual were proximate to and talking with the firstindividual (such as both individuals being in a same room together).

Block 320 states execute the electronic call such that the origin of thevoice of the second individual appears to the first individual tooriginate from the sound localization point while the first individualmoves and changes a location and a head orientation with respect to thesound localization point.

As the first individual moves with respect to the sound localizationpoint, the voice of the second individual continues to emanate from ororiginate from a fixed or stationary location at the sound localizationpoint in the environment of the first individual. These movementsinclude the first individual changing his distance to the soundlocalization point and moving or rotating his head with respect to thesound localization point.

A sound localization point can exists as a single point in space (suchas emulating a point source of sound from a person speaking) or as anarea in space (such as a two dimensional (2D) area, a plane, or a threedimensional (3D) volume in space).

Block 330 states maintain the origin of the voice of the secondindividual at the sound localization point but alter a HRTF, aninteraural level difference, and/or an interaural time difference of thesound that the first individual hears in response to the firstindividual moving the location and the head orientation with respect tothe sound localization point.

As the first individual moves with respect to the sound localizationpoint, one or more aspects of the sound are altered to compensate forthe movements such that the sound the first individual hears continuesto be localized at the sound localization point. For example, one ormore of a HRTF, an interaural level difference, and/or an interauraltime difference are altered.

Consider an example in which a first and a second individual that areremote from each other engage in an electronic call. A voice of thesecond individual localizes to the first individual on a chair that issix feet directly in front of the first individual. During theelectronic call, the first individual moves closer to the chair whilethe voice of the second individual remains unmoved on the chair. Inresponse to this movement of the first individual, a sound intensity ofthe voice of the second individual increases inversely proportional to asquare of the distance from the ears of the first individual to thesound localization point at the chair. This change in sound intensityoccurs in real time as the first individual moves closer to the chair.

Continuing with this example of an electronic call, the first individualrotates his head to his right while listening to the second individual.When the first individual was directly in front of the soundlocalization point, the voice of the second individual reached both earsof the first individual at the same time. When the first individualrotates his head to the right, however, the voice of the secondindividual would first reach the left ear and then reach the right earof the first individual. The voice of the second individual is adjustedto provide an interaural time difference and a shadowing effect thatcompensates for the degree of rotation of the head of the firstindividual.

FIG. 4 is a method to adjust sound that a listener hears as a talkermoves with respect to a virtual microphone point (VMP).

Block 400 states designate a virtual microphone point in empty spacethat is away from and proximate to a talker and that simulates alocation of a listener with whom the talker speaks.

By way of example, the virtual microphone point can be several inches toseveral feet or farther from the talker. A person or an electronicdevice can establish the virtual microphone point, such as designating adistance from the talker to the virtual microphone point and ahorizontal angle and a vertical angle from a head of the talker to thevirtual microphone point.

Block 410 states determine a location and a head orientation of thetalker with respect to the virtual microphone point in empty space.

By way of example, the virtual microphone point represents a mouth andhead of the listener. A determination is made of the distance from theear or ears of the talker to this point and a head orientation of thetalker with respect to this point.

Block 420 states adjust sound that the listener hears the talker speakas the talker moves with respect to the virtual microphone point inempty space such that an origin of the sound that the listener hearsfollows the location and the head orientation of the talker.

By way of example, one or more adjustments are made to a HRTF, aninteraural time difference, and an interaural level difference of thesound provided to the listener. Sound can also be adjusted based oncalculations made for sound attenuation and sound reverberation.

Consider an example in which a talker is in an empty room and wearsheadphones or earpieces with microphones that record binaural sound. Avirtual microphone point is twenty feet away from the talker andrepresents a location of a listener or a recording location. Thisvirtual microphone point is actually empty space since the room is emptyexcept for the presence of the talker. The microphones record binauralsound as the talker walks around the room, speaks, and makes sounds(such as footstep sounds). An electronic device tracks a location and ahead orientation of the talker as the talker walks around the room.These locations and head orientations are stored and correlated with thesound being recorded. Adjustments to the sound are made as the talkermoves and changes location and head orientation. For example, soundintensity is adjusted as the talker moves closer to and farther awayfrom the virtual microphone point that was designated as an imaginary,empty point in space. As another example, interaural time differenceschange as the talker moves his head and/or walks around the virtualmicrophone point (i.e., as the talker changes a horizontal and/orvertical angle with respect to the virtual microphone point). Therecorded sound is then provided to a listener that is remote from thetalker. The listener hears the recorded sound as if the listener werepresent in the room with the talker and situated at the virtualmicrophone point.

FIG. 5 is a method to adjust sound that a listener hears as a talkermoves with respect to a virtual microphone point during an electroniccall between the talker and the listener.

Block 500 states designate, in an electronic call between a talker and alistener that are remote from each other, a virtual microphone point inempty space that is away from and proximate to the talker and thatsimulates a location of the listener with whom the talker speaks duringthe electronic call.

For example, the talker designates the virtual microphone point as alocation next to the talker, and this location represents a location ofwhere the listener would be located if the listener were physicallypresent with the talker. This location is located where the listenerwould be standing, sitting, or otherwise located if the two people weretalking to each other in person.

Block 510 states determine a location and a head orientation of thetalker with respect to the virtual microphone point in empty space.

The virtual microphone point can include a simulated listener with asimulated body that includes a head. This simulated head can haveattributes such as a face, ears, mouth, head orientation, etc. Thelocation and the head orientation of the actual listener can bedetermined with respect to these attributes of the simulated listener.For example, a determination is made as to the head orientation of thetalker with respect to the head orientation of the simulated listener.For instance, the talker is looking toward, facing, and speakingdirectly at the simulated listener (e.g., as if the listener and thetalker were standing, facing each other, and talking).

Block 520 states adjust sound that the listener hears the talker speakas the talker moves with respect to the virtual microphone point suchthat the listener can determine changes to the location and to the headorientation of the talker with respect to the virtual microphone point.

Sound adjustments are made to emulate a sound that the listener wouldhear if the listener and the talker were talking to each other in personwith the listener being located and orientated at the location of thevirtual microphone point. In other words, a determination is made as towhat sound the listener would hear if the listener were standing orsitting next to the talker or otherwise physically located at orproximate to the virtual microphone point.

Consider an example in which a first person and a second person engagein an electronic telephone call in which both people wear headphoneswith speakers and microphones to capture and transmit binaural sound.The first person physically sits in a chair that faces an empty secondchair that has a sound localization point and a virtual microphone pointof a simulated or virtual second person. This simulated or virtualsecond person sits in the chair with a head being located four feet fromthe ground and being orientated to face the first person. The secondperson is physically remote from the first person and the virtualmicrophone point. Sound that the second person hears during thetelephone call copies or emulates the sound that the second person wouldhear if the second person were sitting in the chair, facing the firstperson, and having a head located four feet from the ground (i.e.,orientated in the chair as the simulated second person). When the firstperson moves his head orientation with respect to the chair, thenadjustments to the sound that the second person hears are made tocompensate for these changes in head orientation. Likewise, when thefirst person moves a location with respect to the chair (e.g., movestoward or away from the second chair), then adjustments to the soundthat the second person hears are made to compensate for these changes inlocation.

Consider an example in which two people (a first individual and a secondindividual) are communicating with each over an electronic telephonecall. The first individual localizes a voice of the second individual ata first sound localization point and a first virtual microphone pointthat are next to the first individual, and the second individuallocalizes a voice of the first individual at a second sound localizationpoint and second virtual microphone point that are next to the secondindividual. During the conversation and while the second individual istalking to the first individual, the second individual walks toward thesecond sound localization point and the second virtual microphone point(i.e., the point that represents a speaking and/or listening locationfor the first individual). This action causes the intensity of soundthat the first individual hears to increase since the second personwalks closer to the virtual microphone point. As the second individualwalks toward the second virtual microphone point, the voice of thesecond individual becomes louder for the first individual. Increasingthe volume of the sound in this manner simulates or emulates a scenarioin which the first and second individuals were physically together andtalking with the second individual walking towards the first individual.

The sound localization point and/or virtual microphone point can be asingle location or multiple different locations, such as one or morepoints or areas that represent a source or origin of the sound or sourcefor recording or capturing sound. For example, a point in spacerepresents a location of an ear of a person or a mouth of a person eventhough these points are actually empty (i.e., the person or anotherobject is not located at this point). As another example, the soundlocalization point and/or virtual microphone point have a shape and sizethat represent and copy a shape and a size of the origin of the sound.For instance, if the origin of the sound is a bluejay bird, then thesound localization point has a size and shape of a real bluejay bird.

The sound localization point and virtual microphone points can emulateactions of the object that the sound localization point and virtualmicrophone point represent. Consider an example in which the soundlocalization point represents a chirping bluejay bird. Movements andhabits of a real bluejay bird are incorporated into the soundlocalization point that emulates the bluejay bird. For instance, thesound localization point moves to emulate a live, moving bluejay birdthat is chirping in a tree. These movements and actions can representthe real bluejay bird from whom the sound was captured, or the movementsand actions can represent characteristics of the species. Consider anexample in which the virtual microphone point represents a head and bodyof a listener, and this point moves to emulate customary, habitual,previous, projected, or real-time movements of the listener.

The sound localization point and virtual microphone point can also existat a location that is occupied by an inanimate object (i.e., an objectnot endowed with life). This inanimate object can copy the real objectthat provides or hears the sound. For example, sound from a real bluejaybird emanates from a sound localization point of a plastic, artificialbluejay bird. This artificial bluejay does not actually emit sound.Instead, binaural sound that a listener hears appears to originate froma location in space that occurs at the artificial bluejay bird. Asanother example, a manikin represents a virtual microphone point for aremote listener while a talker talks to the manikin.

The inanimate object can be unrelated to the real object that providesthe sound. For example, sound from a real person emanates from a soundlocalization point of a wooden chair. No sound originates from the chairor even near the wooden chair. Instead, the sound is localized to thelistener to appear to emanate from or originate from the wooden chair.As another example, a talker designates a virtual microphone point as anempty chair. This chair does not actually include microphones since theactual or physical microphones are located elsewhere, such as beinglocated on, with, or near the talker.

FIG. 6 is a method to designate sound localization points forindividuals during an electronic call.

Block 600 states commence an electronic call between a first individual,a second individual, and a third individual that are remote from eachother.

Each individual exists at a different geographical location, such asbeing in different rooms, buildings, cities, states, countries, computergenerated virtual spaces, etc. Further, each individual has anelectronic device that assists in executing the electronic call.

Block 610 states designate, for the first individual, sound localizationpoints that simulate locations in empty space from where origins ofvoices of the second individual and the third individual occur for thefirst individual.

A different sound localization point is designated for the secondindividual and for the third individual. For example, these soundlocalization points represent a location of the physical bodies of thesecond individual and the third individual, such as being at locationswhere these individuals would be if they were present with the firstindividual.

Block 620 states execute the electronic call such that the origin of thevoice of the second individual appears to the first individual tooriginate from the sound localization point that simulates the locationin empty space of the second individual and such that the origin of thevoice of the third individual appears to the first individual tooriginate from the sound localization point that simulates the locationin empty space of the third individual.

Consider an example in which a first person desires to have a conferencecall with a second individual and a third individual. The first personsits at a large wooden table that is located in an office conferenceroom. A sound localization point for the second individual is designatedat a first empty chair at the table, and a sound localization point forthe third individual is designated at a second empty chair at the table.During the conference call, a voice of the second individual that thefirst individual hears appears to originate from the first empty chair,and a voice of the third individual that the first individual hearsappears to originate from the second empty chair.

Consider an example in which a first person engages in an electroniccall with a second person and a third person that are remote from thefirst person. From a point-of-view of the first person, a voice of thesecond person localizes on a couch in a family room, and a voice of thethird person localizes in a doorway that is fifteen (15) feet away fromthe couch. The first person wears electronic glasses that includemicrophones that capture sound and transmit the sound to the second andthird persons. When the first person talks in the family room, soundtransmits to the second and third persons based on a head orientation ofthe first person and a distance between the localization points and thefirst person. During the call, the first person walks to the couch,turns his head away from the doorway, and speaks in a low voice to thesound localization point of the second person on the couch. The secondperson hears this voice, but the third person is not able to hear thevoice since the sound provided to the third person is adjusted based ona distance to the third person's localization point at the doorway and ahead orientation of the first person away from the third person'slocalization point. Sound transmits to the second and third persons asif they were present in the family room at their respective localizationpoints.

An electronic device can intelligently assign locations for one or moresound localization points or virtual microphone points. Selection of thelocation can be based on, for example, available space near thelistener, location of another person, previous assignments of soundlocalization or virtual microphone points, type or origin of the sound,environment in which the listener is located, objects near the person, asocial status or personal characteristics of a person, a person withwhom the listener is communicating, time of arrival or reservation orother time-related property, etc.

Consider an example in which a first individual engages in a conferencecall with a second individual and a third individual who are localizedat chairs around a conference table. A fourth individual decides to jointhis conference call, and a sound localization point for this fourthindividual is automatically located in an empty chair at the conferencetable such that the sound localization points for the second, third, andfourth individuals are equally spaced around the conference table.

A designation of a sound localization point can be based on tracking andlocation information of a person. Consider an example in which a bosswalks into an office of his employee and habitually stands at or near adoorway while talking to the employee in the office. This location ofthe doorway where the boss stands in the office is a preferable,habitual, or favorite location since the boss repeatedly stood there onnumerous previous occasions. Subsequently, the boss telephones theemployee while the employee is located in the office. A voice of theboss automatically localizes to the location in the doorway.

Consider an example in which an individual sits on a park bench next toa playground that is void of other people. The individual listens tosounds of singing birds that are localized to a tree next to the parkbench. The individual interacts with his smartphone and selects theaddition of children to his audial proximity. A software programdetermines a GPS location of the individual and determines an existenceof a playground nearby. The software program intelligently localizessounds of children to exist at the playground. The individual sits atthe park bench and listens to birds singing in the tree and childrenplaying on the playground even though the tree is void of any birds andthe playground is void of any children.

Intelligent localization of an origin of sound can also occur based on alocation and/or orientation of the listener. For example, an individualdesignates telephone calls to have sound localization points four feetfrom his face. When an incoming call occurs, a location and orientationof the face of the individual are determined in order to place the soundlocalization point of the caller at the designated location.

Intelligent localization of an origin of sound can also occur based onparticipants in a call. Different individuals are assigned to differentsound localization points. For example, while a man is in his bed, hiswife calls. Her voice is localized to a location adjacent the man on thebed. After the call is finished, the man receives another call from hisbrother. The voice of the brother localizes to a doorway in the bedroomwhile the man is in his bed.

Intelligent localization of an origin of sound can also occur based onother events, such as time of day. Sounds are localized to differentlocations depending on what time of day the call occurs. For example,calls with an individual that occur in the morning are localized fivefeet from the individual, and calls that occur in the afternoon orevening are localized eight feet from the individual.

Consider an example in which a person carries as HPED that communicateswith earpieces that have speakers. The HPED determines a GlobalPositioning System (GPS) location of the person and determines that theperson is located in a public coffee shop. The HPED receives a telephonecall and positions, based on the GPS information, a sound localizationpoint (SLP) and voice microphone point (VMP) of the caller are placedproximate to a head of the person (e.g., between one and three feet froma face and/or mouth of the person). The person is in a public place andprefers not to speak loudly during the telephone call so the SLP and VMPare close to the face and mouth of the person. Later, the person goeshome to his apartment and receives a telephone call. The HPED determinesa GPS location of the person being home and positions, based on the GPSinformation, a SLP and a VMP of the caller in front of the person (e.g.,between three and ten feet from a face and/or mouth of the person). Theperson is in a private place (i.e., his home) and is comfortablyspeaking more loudly than while in the public place during the telephonecall so the SLP and VMP are farther away from the face and mouth of theperson. As such, a location of the SLP and VMP are based on anelectronic device determining a location of the person (such as being ina public or private location, being proximate to other persons, beingproximate to strangers versus friends, etc.). For instance, a publicplace is a location that is open to the public (e.g., a place with aright of common passage), and private place is a location that is notopen to the public (e.g., a house, an apartment, or an office room).

The sound localization point or virtual microphone point can also bechanged so as not to conflict with an object, a location, another SLP,another VMP, a person, or an event. For example, a SLP defaults to apoint in space that is five feet from a listener in a certain direction,but a wall in a room is located four feet from the listener in thisdirection. In this example, the SLP changes to be three feet from thelistener since this location is not beyond the wall. For example, whilea person drives a car, a SLP of a participant during a telephone calloccurs in an empty passenger seat next to the driver. Anotherparticipant calls the driver during the telephone call, and a second SLPis added to an empty back seat in the car since the front passenger seatis already occupied with a SLP.

A default SLP or VMP can also be changed when such a point is notpractical or convenient. For example, a person designates a SLP fortelephone calls to be five feet in front of his face. The personreceives a phone call while driving a vehicle, but the SLP would beoutside of the vehicle in front of the windshield and hence not in apractical or convenient location. The SLP is automatically changed to betwo feet to one side of the person and hence in the vehicle.

FIG. 7 is a method to adjust sound based on a physical environment of anindividual.

Block 700 states capture sound at a first geographical location havingfirst environmental conditions.

This sound is captured at a first geographical location, such as in aroom, in a building, outdoors, etc. The first geographical location hasa first set of physical, environmental, or ambient conditions, such astemperature, humidity, wind, terrain, elevation, objects (manmade ornatural) at the location, size and/or shape of structure in which thesound is captured (e.g., if sound captured indoors as opposed tocaptured outdoors), etc.

Block 710 states determine, for an individual to receive the sound,second environmental conditions at a second geographical location of theindividual.

The origin of the sound is captured at a first geographical locationwith first environmental conditions. The individual to receive the soundexists at a second geographical location with second environmentalconditions that are different than the first environmental conditions.

The conditions, objects, and circumstances that surround an individualor a thing creates an environment that has an impact on how soundtransmits and how this sound is heard. The environmental conditions orphysical environment include, but are not limited to, movable objects(such as furniture, electronic and non-electronic devices, people,things, etc.), immovable objects (such as walls, doorways, ceilings,rooms, floors, structures, etc.), size and shape of a room or a locationin which sound propagates, natural objects (such as trees, grass,plants, etc.), manmade objects, weather or ambient environmentalconditions (such as temperature, humidity, wind, precipitation, etc.),background or ambient noise at the environment, electromagneticinterference, data bandwidth or data latency limitations or fluctuationswithin a network of the environment or adjacent networks, andlimitations and fluctuations in rendering speed, resolution, andaccuracy of computer generated virtual locations.

Consider an example in which the sound is captured from a firstindividual located in one city and state while the first individual islocated in a recording studio sound room. The sound is then provided toa second individual located in another city and state while the secondindividual is standing outdoors in a snow covered field.

Block 720 states adjust, based on the second environmental conditions atthe second geographical location, the sound such that the soundsimulates a natural sound that the individual would hear if the originof the sound occurred in the second environmental conditions at thesecond geographical location with the individual.

Sound is adjusted to compensate for a physical environment in which alistener hears the sound so the sound appears to the listener to haveemanated from or originated in this physical environment even though thesound actually originated from a different physical environment. Soundthat the listener hears more closely emulates sound that the listenerwould hear if the sound actually originated from the sound localizationpoint in the physical environment of the listener.

In the physical environment, various factors can affect how soundreverberates, reflects, refracts, and attenuates. These factors include,but are not limited to, geometric spreading, atmospheric effects, andsurface effects. The effects on sound from these factors can bemeasured, estimated, stored, retrieved, and applied as one or moreadjustments to the sound.

Geometric spreading includes spherical and cylindrical spreading ofsound. For example, in spherical spreading from a point source, thesound level generally reduces according to the inverse square law (e.g.,sound reduces by a known or given amount for each doubling of thedistance from the source of the sound).

Atmospheric effects include molecular relaxation and viscosity effects.Temperature and humidity of the atmosphere of the propagating sounddetermine an amount of absorption. Absorptions for different frequenciesat given temperatures and humidity can be stored and obtained fromtables and/or graphs. For example, sound at a frequency of 2 kHz has anabsorption rate of about 0.25 dB/100 meters for 30% relative humidity at68 degree Fahrenheit.

Surface effects include ground absorption and attenuation due tobarriers. For example, attenuation results from acoustic energy losseson reflection when the sound propagates over ground. Smooth and hardsurfaces (such as tile and wood) produce little absorption, whereassofter surfaces (such as carpet and grass) result in greater absorption.Reflection along the surface can also reduce the sound level. Forinstance, a ground effect occurs when sound reflected from the grounddestructively interferes with the direct wave when the direct wavetravels near the ground.

Sound reverberation provides a listener with clues with regard to aspatial context of the sound, such as giving the listener informationabout a size, shape, and content of a room. A geometric model of an areacan be used to provide a reverberation modeling system. For example, adirection and time of sound impulse reflections are calculated with raytracing, and these reflections are rendered per a delay time and anattenuation filter for transmission and reflection losses. Recursive orloop filters can be used to emulate reverberations that occur later intime.

Objects near the listener can be simulated with diffraction modeling.When a sound impulse strikes an object, a path of this sound diffractsaround the object. Sound with a high frequency (e.g., a wavelengthsmaller than the object) will shadow and attenuate. One or more low-passfilters can be used for various cutoff frequencies to simulate a size ofoccluding objects.

Consider an example in which reverberation for an actual room or avirtual room is calculated per the following equation (Sabine'sequation):

RT=0.16(V/SA),

where RT is the reverberation time, V is the volume of the room, S isthe total surface area, and A is the average absorption coefficient ofroom surfaces. Sound absorption coefficients can be obtained frommemory, such as sound absorption coefficient tables. As an example, adigital reverberation algorithm simulates time domain and frequencydomain responses of the room in order to generate a reverberationeffect. As another example, one or more feedback delay circuits create adelaying or echoing effect on the sound.

Consider an example in which binaural sound is captured at microphoneslocated on an electronic device with little or no discernible effectsfrom sound reflection, refraction, and attenuation. This sound istransmitted and played to a listener who wears headphones and who standsoutside with a sound localization point that is twenty (20) feet awayfrom the listener. The sound is adjusted to account for the outdoorphysical environment of the listener so the sound that the listenerhears through the headphones emulates the sound that the listener wouldhear if the speaker were standing at the sound localization point twentyfeet from the listener. The sound adjustments can be calculated from oneor more of equations and information relating to spreading, absorption,ground configuration, obstacles, pressure, wind, temperature, andhumidity.

By way of example, the speed of sound, C, is given by the followingequation:

C ²=(∂p/∂ρ)_(s),

where p is the pressure, ρ is the density, and the derivative is takenadiabatically (i.e., at constant entropy per particle, s). For example,the speed of sound at twenty degrees Celsius (20° C.) and 1 atmosphereis 331.5 meters/second.

The decibel (dB) or sound pressure level (SPL) provides a quantificationfor sound pressure levels relative to a logarithmic scale. The intensitylevel (IL) of sound intensity (I) is given by the following equation:

IL=10 log₁₀(I/I _(ref)) dB,

where I_(ref) is a reference intensity.

The sound pressure level (SPL) is given by the following equation:

SPL=20 log₁₀(P _(e) /P _(ref)) dB,

where P_(e) is a measured effective pressure amplitude of the sound waveand P_(ref) is the reference effective pressure amplitude.

Sound attenuation through the outdoor air (A_(T)) is given by thefollowing equation:

A _(T)=10 log₁₀(L _(ps) /L _(pr))=20 log₁₀(P _(s) /P _(r)) dB,

where L_(ps) is the sound pressure level of the root mean square soundpressure P_(s) at a distance s from the source, and L_(pr) is the soundpressure level with a root mean square sound pressure P_(r) measured ata distances r from the source. The total attenuation (A_(T)) is the sumof the attenuation due to geometric spreading (A_(s)) plus atmosphericabsorption (A_(a)) plus other effects (A_(e), such as attenuation fromthe ground, refraction, scattering, etc.).

Here, attenuation due to geometric spreading (A_(s)) is given by thefollowing equation for a spherical wave:

A _(s)=20 log₁₀(r ₂ /r ₁) dB,

where A_(s) is given as the distance between two points r₁ and r₂ from asource.

Here, attenuation due to atmospheric absorption (A_(a)) is given by thefollowing equation for a spherical wave:

A _(a)=−20 log₁₀(exp(−αr)) dB,

where r is the path length of the wave, and α is the attenuationcoefficient.

Further, sound is reflected from a surface in which the angle ofreflection of the sound wave is equal to the angle of incidence of thewave such that reflective waves can cause constructive and destructiveinterference.

Further yet, depending on the geometric configuration of nearby objects,sound can diffract and spread out beyond an opening or around obstacles.Diffraction relates to the wavelength of the sound with high frequenciestending to propagate more directly and low frequencies tending to passfrom behind objects.

Consider an example in which a first individual communicates via anelectronic phone call with a remotely located second individual. Thefirst individual wears headphones or an earpiece that provides binauralsound. A voice of the second individual is localized to a point that isten feet away from the first individual while the first individual sitsin his office. The voice of the second individual appears to originatein a point in space in the office, and this point in space is the soundlocalization point of the second individual. So, from the point-of-viewof the first individual, the voice of the second individual originatesin the office as if the second individual were present in the office andtalking to the first individual.

In this example, the sound that the first individual hears is capturedat the location of the second individual. For example, as the secondindividual speaks at the remote location, the sound is processed intobinaural sound or processed as captured binaural sound, transmitted, andpresented to the first individual so that the first individual localizesthe sound at the sound localization point in the office. The physicalenvironment in which the first individual is located, however, does notaffect the sound since the sound is captured at the location of thesecond individual and then provided to the first individual throughheadphones or earpieces.

The sound that this first individual hears can be adjusted to moreclosely emulate the natural sound that the first individual would hearif the second individual were physically standing or sitting at thesound localization point in the office. These adjustments includemodifying the sound to compensate for the physical environment of thefirst individual. These modifications include adjusting the sound forobjects located in the office, a shape of the office, a size of theoffice, material from which the office is made or composed (e.g., glasswindows, concrete floors, wooden walls, a plaster ceiling, etc.). Inother words, determine how the sound would propagate from the soundlocalization point to the first individual that sits in the office. Forexample, objects between the sound localization point (such as a chair,a table, carpeted floor, plants, etc.) and the first individual wouldaffect how the sound propagates to the first individual. As anotherexample, a shape and size of the office will determine whatreverberations would occur if the second individual were speaking to thefirst individual from the sound localization point. A composition of thematerials that form the walls, floors, and ceilings would also affectreverberations, echoes, reflections, or sound decay. These physicalaspects of the environment are used to determine how to artificiallyadjust the sound that the first individual hears so this sound emulatesthe sound that the first individual would hear if the sound actuallyoriginated from the second individual at the sound localization point.

Adjusting the sound for environmental conditions is different thanadding sounds, such as adding background noises. Adjusting the sound forenvironmental conditions processes the sound so it emulates the soundthat would be heard if the sound originated at the sound localizationpoint.

Consider an example in which a binaural sound recording of a train playsto two different people. A first person is located in a winterenvironment with high humidity, a flat terrain, and snow on the ground.A second person is located in a summer environment with low humidity anda hilly terrain with surrounding woods. A sound localization point foreach person is two kilometers away and directly in front of the person.Before being played to the first and second persons, the sound recordingis processed to compensate for the environmental conditions in which theperson is located.

Sound attenuation per Stoke's law will change the sound that the firstperson hears versus the sound that the second person hears. Attenuationof the sound is proportional to the dynamic viscosity and the square ofthe sound frequency, and reciprocally proportional to the fluid densityand speed of sound (noting that volume viscosity also affectsattenuation). Sound attenuates per the following equation:

A(d)=A ₀ e ^(−αd),

where A(d) is the amplitude of the sound wave at a given distance, A₀ isthe amplitude of the un-attenuated sound wave, d is the distancetraveled, and α is the attenuation coefficient.

For example, sound attenuates differently according to both humidity andtemperature. Dry air absorbs more acoustic energy than moist air, andsound travels faster in warmer air. Thus, given the environmentaleffects of humidity and temperature alone, the first and second personwill hear a different sound since the recording is adjusted differentlyfor different environmental conditions.

Furthermore, acoustic impedance for objects of different materials canbe calculated with the following equation:

Z=pV,

where Z is acoustic impedance of a material, p is a density of thematerial, and V is acoustic velocity.

Sound waves are also reflected at boundaries having different acousticimpedances (known as impedance mismatches). An amount of reflection ofan incident wave can be calculated when the material impedances areknown for materials on both sides of the boundary per the followingequation:

R=[(Z ₂ −Z ₁)/(Z ₂ +Z ₁)]²,

where R is the reflection coefficient, Z₁ is the impedance of the firstmaterial, and Z₂ is the impedance of the second material.

Furthermore, sound reflection can be calculated per the followingequation:

R=a _(r) /a _(i),

where R is the reflection coefficient, a_(r) is reflected waveamplitude, and a_(i) is the incident wave amplitude.

Values for sound adjustments can be calculated and/or estimated for realobjects and real physical environments, and these numbers can be used tosimulate artificial objects and artificial physical environments.

FIG. 8 is a method to adjust sound based on an artificial environment.

Block 800 states capture sound at a first geographical location havingenvironmental conditions.

This sound is captured at a first geographical location, such as in aroom, in a building, outdoors, etc. The first geographical location hasa set of physical, environmental, or ambient conditions, such astemperature, humidity, wind, terrain, elevation, objects (manmade ornatural) at the location, size and/or shape of structure in which thesound is captured (e.g., if sound captured indoors as opposed tocaptured outdoors), etc.

Block 810 states determine, for an individual to receive the sound,artificial environmental conditions at a second geographical location ofthe individual.

A set of artificial environmental conditions is generated for theindividual to receive the sound. These artificial environmentalconditions are different than the environmental conditions where thesound was captured and/or where the individual is located. Theseenvironmental conditions are fabricated to replicate a physicalenvironment, such as a physical environment in which the individual isnot located, or a computer generated virtual environment.

Block 820 states adjust, based on the artificial environmentalconditions, the sound such that the sound simulates a natural sound thatthe individual would hear if the origin of the sound occurred in theartificial environmental conditions at the second geographical locationwith the individual.

Consider an example in which a first and second individual have atelephone conversation. An electronic device captures sound from thefirst individual while the first individual is located in a bedroom of ahouse. Another electronic device provides this sound to the secondindividual that is located in a small cubicle in an office building. Thesecond individual, however, desires to have the voice of the firstindividual localized at a distance of ten feet while the first andsecond individuals are standing on an ocean beach. The cubicle (having alength and width of six feet by six feet) is too small to localize thevoice ten feet from the second individual and still be within thecubicle. Further, an environment of the cubicle in the office is notsimilar to an ocean beach environment. So, the sound is processed andadjusted such that the voice of the first individual is perceived in anartificial environment of being ten feet away from the second individualwhile the two individuals are standing on an ocean beach. By way ofexample, the sound is modified as to one or more of HRTFs, attenuation,environmental conditions, interaural level differences, interaural timedifferences, speed, frequency, amplitude, reflection, refraction, etc.The second individual thus hears the conversation as if the first andsecond individuals were standing on the beach.

FIG. 9 is a method to adjust HRTFs of an individual during an electroniccall.

Block 900 states execute an electronic call between a first individualand a second individual such that an origin of a voice of the secondindividual appears to the first individual to originate from a soundlocalization point that simulates a location in empty space of thesecond individual.

The first individual localizes a voice of the second individual at thesound localization point. The electronic call can include other soundsas well, such as ambient or environmental sounds and artificial orcomputer generated sounds. These other sounds can be localized atlocations different than the sound localization point. For example, thefirst individual localizes a voice of the second individual at six feetaway and simultaneously localizes voices of children playing twenty feetaway and behind the sound localization point of the second individual.

Block 910 states monitor, during the electronic call, movements of ahead location and/or head orientation of the first individual inresponse to the first individual localizing sounds.

For example, an electronic device tracks or monitors a position and/or alocation of the head of the first individual. For instance, adetermination is made as to whether and/or when the head turns left orright, turns up or down, or rotates back and forth. These movements canbe measured with respect to a location or a position, such as measuringmovements with respect to a sound localization point, measuringmovements with respect to a head orientation at a particular time,measuring changes to head orientation at a specific time or during aninterval of time, and measuring head orientation in response to one ormore sounds being provided to the first individual. The movements inresponse to the sounds provided may be deliberate voluntary movementsfor the purpose of adjusting HRTFs or movements made for anotherpurpose, such as a game or other activity.

Block 920 states adjust, during the electronic call, stored head-relatedtransfer functions (HRTFs) of the first individual to more accuratelysimulate real HRTFs of the first individual in response to the movementsof the head location and/or head orientation of the first individual.The stored HRTFs and other localization profile data may be fromprevious use by the individual or copied from another individual or froma database of common approximate profiles.

The HRTFs of the first individual are adjusted in real time during theelectronic call to more closely match or approximate natural or realHRTFs for the first individual.

Interpolation of the angular positions for a sound source can lead toconfusion or sound localization errors for the listener (e.g.,front-back confusion on a sound localization point). By way of example,these errors can be corrected with real-time monitoring of head movementand orientation in response to generated sounds at sound localizationpoints, extraction and interpretation of keywords from listenerconversations, listener input, listener interpretation of the properlocalization being influenced by visual stimulation such as a picture oricon representing the second individual being positioned on a visualdisplay relative to other objects on the display so as to give cluesabout the spatial arrangement to the first individual as he sees thevisual display, and other methods.

A sound localization point can be placed in an area known as the Cone ofConfusion. The listener may localize the sound to a specific location inthis Cone of Confusion, and a head orientation recorded for the angularposition, θ, of this gaze. A specific set of interaural time differences(ITDs), interaural level differences (ILDs), and HRTFs can be developedfor this gaze location. HRTF data set can be continually updated inreal-time while a listener localizes sound in order to more closelymatch this HRTF data set with characteristics of the listener's anatomy.

Consider an example in which a first and a second individual engage inan electronic call. A sound localization point of a voice of the secondindividual appears directly in front of the first individual to emulatethe two individuals facing each other. For example, the first isinstructed to face the sound localization point that is located at anazimuth angle of zero degrees (0°). The first individual complies, but adetermination is made during the electronic call that the firstindividual faces a position with an azimuth angle of ten degrees (10°).Thus, a location of the perceived sound localization point (i.e., wherethe first individual is looking) and a location of the intended orcomputed sound localization point are offset by ten degrees (10°).Adjustments are made to the HRTFs of the first individual to compensatefor this difference or discrepancy. With these adjustments, stored HRTFsfor the first individual will more closely match or represent real,natural, or true HRTFs for the individual. After the adjustments aremade to the HRTFs, the first individual will perceive the accurateposition of the sound localization point of the second individual (e.g.,during a subsequent electronic call between the first and secondindividuals).

Adjustments to HRTFs are not limited to being based on a headorientation of an individual. Consider the example in which the firstand the second individual engage in the electronic call such that thesound localization point of the voice of the second individual appearsdirectly in front of the first individual. During the call, the firstindividual hears children laughing behind the second individual andstates, “Who are the children laughing behind you?” The laughingchildren, however, are not located behind the second individual, but arelocated in front of the second individual. The second individualresponds to the question and says, “Those are my nephews; they areplaying on the couch in front of me, not behind me.” Keywords areextracted from this conversation to determine an error in thelocalization of sounds of the first individual. HRTFs of the firstindividual are adjusted to compensate for this error in soundlocalization. Here, a conversation between the first and the secondindividual provided information that assisted in determining how toadjust stored HRTFs for the first individual. As the accuracy of theHRTFs is improved with each call, they may be updated and storedanonymously on a worldwide public database of crowdsourced profiles.

FIG. 10 is a method to execute recorded sound at a sound localizationpoint.

Block 1000 states record sound.

Sound can be recorded, captured, stored, retrieved, transmitted,generated, and/or processed.

Block 1010 states provide a sound localization point in empty space forthe recorded sound.

For example, the sound localization point for the sound is an originlocation of where the sound was recorded. For instance, a dummy headwith binaural microphones records sound that originates twenty feet awayat a vertical angle of thirty degrees (30°) and a horizontal angle ofsouth forty-five degrees east (S45° E). As another example, a computergenerates binaural sound that localizes to a listener at an origin ofthree feet away at vertical and horizontal angles of zero degrees (0°).

Block 1020 states determine an event that triggers playback of therecorded sound.

One or more events can trigger playback, transmission, retrieval,recovery, and/or processing of the sound. By way of example, theseevents include, but are not limited to, an action or event that a userinitiates and/or performs and an action or event that an electronicdevice initiates and/or performs.

Block 1030 states execute, to a listener and in response to the trigger,the recorded sound at the sound localization point in empty space suchthat the listener can localize the recorded sound to originate from thesound localization point.

Consider an example in which a first person wears binaural microphonesand records a voice message for a second person. The first persondesignates a GPS location of an office room for activating the voicemessage that is stored on a cloud server. Later, the second personenters the designated office room, and this action triggers retrieval ofthe recorded voice message. The recorded voice message automaticallyplays for the second person upon entering the office room.

Consider an example in which a mother makes a binaural recording for herdaughter. The mother designates the recording to play in the bedroom ofher daughter at a trigger time of 6:00 a.m. and also designates a soundlocalization point that is three feet away from the bed. At 6:00 a.m.while the daughter is sleeping in her bed, the recording of the motherbegins to play at the sound localization in the bedroom. The daughterlocalizes the sound of the recording to the sound localization pointthat the mother previously designated.

FIG. 11 is a method to select HRTFs for a listener.

Block 1100 states determine one or more physical attributes of alistener.

A physical attribute includes human anatomy or the structure of thehuman body. By way of example, physical attributes of a human includebut are not limited to, appearance and position of body parts, locationsof body parts, size and shape of body parts, and spatial relation ofbody parts with each other (e.g., a distance between two body parts).

The physical attribute can be captured, stored, processed, and/ortransmitted. For example, an electronic device captures a digital imageor a video frame of a physical attribute of the listener. For instance,a camera takes a picture of a face, ear, body part, or body of thelistener.

Block 1110 states compare the one or more physical attributes of thelistener with one or more physical attributes of individuals with storedHRTFs.

HRTFs for individuals are stored and retrievable from memory, such as ananonymous database. These HRTFs include known HRTFs that are measured orcalculated from or tested and refined by individuals and dummies.

A comparison is made between one or more of the physical attributes ofthe listener with one or more of the physical attributes of individualswith stored and known HRTFs. For example, a comparison is made between asize and shape of a head (including the ear) of a listener with sizesand shapes of heads (including ears) of the individuals with knownHRTFs.

Block 1120 states determine, based on the comparison, a match and/orsimilarity between the one or more physical attributes of the listenerand the one or more physical attributes of individuals with storedHRTFs.

The comparison reveals a match or similarity between physical attributesof the listener and physical attributes of the individuals. For example,select one or more individuals with whom the listener has similar facialfeatures, such as similar size and shape head and/or ears. For instance,a determination is made that the listener more closely resembles anindividual having a similar face, having ears with a similar or likesize, shape, and location, having a similar facial and hair profile,having common or equivalent sizes of noses, ears, mouths, etc.

Block 1130 states select, based on the match and/or similarity with thestored HRTFs, a set of HRTFs for the listener.

Individuals have a unique set of HRTFs since each individual has aunique anatomical structure and unique correlation and mapping of soundto a localization point. HRTFs for an individual can be measured orselected for the individual. Consider an example in which known HRTFsare stored for individuals in a database. These HRTFs are mapped to oneor more physical attributes and/or anatomical characteristics thatinclude, but are not limited to, a size and shape of the head, a sizeand a shape of a torso and shoulders, an amount and a style of hair,clothing worn (e.g., whether a person wears a hat), height, weight, etc.Physical attributes of a listener are determined, and then thesephysical attributes are compared with the physical attributes of theindividuals with known HRTFs stored in the database. This comparisonreveals a similarity or match between the listener and one or morestored individuals. Based on this similarity or match, a set of HRTFs isretrieved from the database and selected as the HRTFs for the listener.For instance, facial recognition software compares images of the head ofthe listener with images of heads of the stored individuals anddetermines a match based on similar physical features, such as headsize, head shape, pinna shape and size, pinna location on the head, andfacial characteristics (e.g., size, shape, and location of nose, eyes,mouth, cheeks, chin, ears, etc.). The software may also measure orestimate distances and angles of body parts and facial features based onthe images or calculated from other measurements, and these measurementsor the results of functions of these measurements are used to search adatabase for a predefined HRTF set stored from a user with similarmeasurements.

Consider an example in which a listener talks on a smartphone thatincludes a camera. When the listener moves the smartphone to her ear,the smartphone takes a picture of ear. An image of this ear is comparedagainst a database of ear images to determine another ear having asimilar or same size and shape. When a match is found, HRTFs or HRIRsfor the discovered ear are retrieved and applied to the listener.

Consider an example in which a listener takes a photograph of his ownface and posts the photograph to a social networking website. A facialrecognition software program compares the face of the individual withstored faces with known HRTFs. A face of an individual is discoveredthat most closely matches anatomical features of the face of thelistener. HRTFs for this individual are retrieved and provided toprocess sound for the listener since the two individuals have similarphysical facial attributes.

Consider an example in which a near fit occurs or no suitable match isfound. A user or electronic device adjusts the near fit (e.g., using amethod herein), stores it, refines it over time, and provides it to apublic or private database of crowdsourced profiles.

FIG. 12 is a method to calculate HRIRs for a listener.

Block 1200 states determine a sound location of a talking person thatwears a wearable electronic device with microphones with respect to alistening person that wears a wearable electronic device withmicrophones.

Positions of one or more of the microphones, the wearable electronicdevices, and the persons can be determined. For example, a distance orposition between the wearable electronic devices, a location of a mouthor a point source of the sound of the talking person, horizontal and/orvertical angles between the wearable electronic devices and/or personsand/or microphones. For instance, a distance and azimuth and elevationangles are determined between the microphone of the listening person andthe mouth of the talking person.

Examples of the wearable electronic device with microphones include, butare not limited to, earpieces, headphones, earphones, electronicglasses, hearing aids, and electronic devices that fit into or near theear.

Block 1210 states measure, with the microphones of the wearableelectronic devices of the talking person and the listening person, soundimpulses from the talking person.

The microphone of the talking person captures sound as it exits themouth of the talking person, and the microphone of the listening personcaptures sound as it travels from the mouth of the talking person to themicrophone.

Block 1220 states calculate, from the measured sound impulses, HRIRs forthe listening person.

One traditional method to measure HRTFs is to place microphones in adummy or human head and then provide sound impulses from speakers to thedummy or human head. Sound impulses are provided for various azimuthangles, and the corresponding HRIRs or HRTFs are measured andcalculated. This method is time-consuming since the dummy head, thehuman head, or the speaker is rotated for each azimuth angle so themicrophone can capture different sound impulses for each angle.

In contrast to the traditional method, an example embodiment capturessound impulses from a talking person that can be stationary or moving(as opposed to capturing sound impulses from a stationary speaker).Further, such sound impulses can be captured to build a set ofuser-specific or customized HRIRs or HRTFs for the listening person.

Further yet, the talking and listening person are not required to be ata specific location, such as a sound studio or controlled soundenvironment. By contrast, the sound impulses can be captured duringconversations that occur during normal or ordinary life activities, suchas capturing the sound impulses at a public location, at an office, in ahome, in a park, etc. Ambient noise and attenuation due to environmentalconditions can be filtered. Furthermore, HRIRs and HRTFs for a personcan be measured and calculated over a period of time while the personengages in conversations with different people or encounters differentsound sources. For instance, a set of customized HRIR or HRTF values fora person can be periodically, continually, or continuously updated orrevised for the person.

A source of the sound impulses can also vary, and this source is notrestricted to speakers. This source can include electronic speakers,people, and other electronic devices that the user encounters during hisor her daily activity. For instance, HRIRs are captured for a personwhile this person wears earpieces with microphones and watches a videofrom a personal computer during the morning. In the afternoon, HRIRs arecaptured for the person while the person talks to another person thatalso wears earpieces with microphones. In the evening, HRIRs arecaptured while the person watches television at home.

Sound captured at the microphone of the talking person providesreference sound impulses for computing the HRIRs of the listeningperson. Changes to these sound impulses occur from interaction with theanatomy of the listening person. Although both the talking person andthe listening person can contribute to transformation of the soundimpulse, a comparison of these transformations can reveal what impactthe listening person has on the transformation of the sound impulse. Forexample, HRTFs are measured at each ear of the talking and listeningpersons. These HRTFs describe the time delays, amplitude, tonaltransformations, etc. for given azimuth and elevation angles. A soundimpulse captured at the talking person has a set of HRTFs, and thissound impulse captured at the listening person has a set of HRTFs. Acomparison of these sets of information reveals what changes were madeto the sound impulse by the anatomy of the listening person.

Consider an example in which a talking person wears electronic glasseswith speakers and microphones in or near his ears, and a listeningperson wears electronic glasses with speakers and microphones in or nearhis ears. HRIRs and HRTFs of the talking person are known. Further, headorientations of the listening person are tracked such that an azimuthangle and a vertical angle can be calculated between the mouth of thetalking person (i.e., the origin of the sound impulses) and the head ofthe listening person. Changes to the sound impulses recorded at themicrophones of the listening person provide information as to how thehead, ears, and torso of the listening person affected the soundimpulses. HRIRs can be calculated from these changes. Further, theserecordings can be made while talking person and/or listening person movewith respect to each other. The head orientation of the listening personand/or talking person are known at a given point in time, and the soundimpulses at this point in time are correlated with the known headorientations.

Consider an example in which a person wears electronic earpieces thatinclude both speakers and microphones. During a phone call, the speakersprovide the person with sound from another individual on the phone call.The microphones capture a voice of the person and provide this voice tothe other individual. When the person is not engaged in a phone call,the microphones capture sound from a sound source that is local to orproximate to the person. For example, this sound source is a television,a radio, a computer, a talking person, or an electronic device thatproduces sound. A determination is made of the head orientation of theperson with respect to the sound source so the recorded sound impulsescan be correlated with the head orientation of the person. For instance,a tracking device in an electronic device tracks and records headorientations and records times for these orientations. Changes to thesound impulses indicate HRIRs for the person such that user-specificHRTFs are calculated.

For example, HRTF data collection and training exercise is presented asa computer game in which sound targets of various audio frequencies are“shot” by a player actuating a trigger while pointing his head in theperceived direction of the sound. The head orientation and shots aremeasured during the game and correlated with the SLPs of the targets inorder to improve the accuracy of the HRTFs for the player.

HRIRs can be recorded for various angles and interpolations made as tonon-recorded angles. For example, azimuth angles are recorded inincrements of about five degrees (5°), and angles between the recordedangles are interpolated. Further, these angles can be recorded over aperiod of time, such as over hours, days, weeks, months, etc. Consideran example in which a person has a conversation with a third party thatfunctions as an origin of sound impulses. During this conversation,sound impulses are recorded for seven different azimuth angles, butthese angles do not provide sufficient data to compute individualized oruser-specific HRIRs for the person. The next day during a subsequentconversation with another third party, additional sound impulses arerecorded for numerous other azimuth angles. Sound impulses are capturedover time to build sufficient data to compute HRIRs and HRTFs that arespecific to the anatomy of the listener. Data from these recordings canalso be used to augment or improve existing HRIRs and HRTFs for theperson.

FIGS. 13A-13D show how ITDs can be measured and calculated.

FIG. 13A shows a sound source 1300 that provides a sound wave 1310 to alistener 1320. Since the listener 1320 is directly in front of andfacing the sound source 1300, the sound wave 1310 arrives at the leftear and the right ear at the same time. The ITD is zero (0) since theazimuth angle is zero degrees (0°).

FIG. 13B shows a graph 1330 of the sound wave arriving at the left earand at the right ear at the same time. The arrival times of the soundwave at each ear are identical, and this provides an auditory clue tothe listener for localizing an origin of the sound wave.

FIG. 13C shows the sound source 1300 that provides a sound wave 1350 toa listener 1320. The listener 1320 is directly in front of the soundwave 1350, but a head of the listener is rotated ninety degrees (90°) tothe right such that the sound wave 1350 arrives at the left ear firstand later in time at the right ear.

FIG. 13D shows a graph 1360 of the sound wave arriving at the left earand subsequently at the right ear. The sound wave at the right ear isoffset by an amount of time required for the sound wave to travel to theright ear. This offset is about 0.6-0.7 milliseconds (msec).

The ITD is dependent on the speed of sound and a difference in distancethe sound travels to reach both ears. When a head of the listener isrotated ninety degrees (90°) with respect to the direction of the sound,then this distance (D) represents a width of the head of the listener.

The ITD can be calculated or estimated knowing information such as thespeed of sound, width of the head of the listener, and angle of rotationof the head or head orientation with respect to the direction of thesound wave. By way of example, if the speed of sound is 761 miles perhour (mph), the width of the human head is seven inches (7″), and thehead is rotated ninety degrees (90°) with respect to the direction ofthe sound such that the sound strikes the left ear first, then it wouldtake approximately 0.63 milli-seconds (msec) for the sound to travelfrom the left ear to the right ear (using a hypothetical instance inwhich the sound propagated to the right ear in a straight line and usingthe formula of distance (D) equals rate (R) times time (T), or D=R×T).More specifically, the change in time is given by the followingequation:

ΔT=D sin θ/R,

where ΔT is the arrival time difference between two ears, D is thedistance between the two ears, θ is the angle of arrival of the soundfrom the source, and R is the speed of sound.

This equation does not take into account that sound travels around thehead, and this added distance causes additional delay. If an assumptionis made that the head is spherical, then the ITD is given by thefollowing equation:

ITD=r(θ+sin(θ))/R,

where ITD is the interaural time delay, r is half the distance betweenthe ears, θ is the angle of arrival of the sound from the source, and Ris the speed of sound.

FIG. 14 shows a graph 1400 of ITDs for various head orientations withrespect to a propagation direction of the sound wave. The X-axis showsangles from the sound source to the head, and the Y-axis showsinteraural time differences in milliseconds. This data can be stored andretrieved to assist in executing example embodiments.

An interaural level difference (ILD) represents a difference in soundpressure levels at each ear. When the head of the listener is rotatedwith respect to the propagation direction of the sound wave, then eachear receives a different sound pressure level from the impacting soundwave. The head of the listener creates an acoustic shadow between thetwo ears. An amount of ILD depends on the head orientation and on afrequency of the sound wave since higher frequency sound waves attenuatemore readily than lower frequency sound waves.

FIG. 15 shows a graph 1500 of ILDs for various sample frequencies acrosshead orientations from 0° to 180° with respect to a propagationdirection of a sound wave. The X-axis shows angles from the sound sourceto the head, and the Y-axis shows interaural level differences indecibels (dBs). This data can be stored and retrieved to assist inexecuting example embodiments.

The ears, face, and head of people alter the amplitude and phase ofsound waves entering each ear. Changes to these waves from the anatomyof the human body are calculated as head-related transfer functions(HRTFs). HRTFs can be measured (e.g., using microphones in ears) and/ormathematically computed and modeled for various locations in space. Forexample, an HRTF is calculated and stored for azimuth and verticalpositions around the head.

HRTFs are functions of frequency and three spatial variables. In farfield distances greater than about one meter, the HRTF attenuatesinversely with range and can be measured and/or mathematicallyestimated. Once HRTFs are known or calculated for discreet angularincrements (such as increments of fifteen degrees (15°) in the azimuthposition), HRTFs can be estimated or interpolated for other angularpositions (e.g., other angular positions, θ, in the far field HRTF ofH(f, θ, φ).

HRTFs (or head-related impulse responses (HRIRs) in the time domain) canbe obtained from measurements of the listener at various angles orobtained from mathematical modeling. For example, a microphone is placedin or near an ear or ear canal of a person to record binaural pressures.A grid of HRIRs at various locations in space around a listener can beused to move the sound localization point around the listener. TheFourier transform of the HRIRs, h(t), for an impulse at a sourcegenerates the HRTFs, H(f), that enable source localization. HRTFs forthe left and right ear can be stored and processed to synthesizebinaural signals from a sound source.

Binaural synthesis transforms a sound source with no positionalinformation to a virtual sound source with respect to a head of alistener. As the listener moves with respect to the sound localizationpoint, HRTFs are changed in response to these movements. Calculationsare made with respect to the relative position and head orientation ofthe listener with respect to the sound localization point or theimaginary point where the listener should be localizing the sound. HRTFscan be retrieved and/or calculated based on the known relative positionand head orientation of the listener with respect to the SLP.

By way of example, binaural synthesis involves convolving a mono soundwith HRIRs to generate a synthetic binaural signal that includesdirectional information of the sound source. This directionalinformation is included in the HRTFs. By way of example, the sound wavesare adjusted with a convolving process that applies a Discreet FourierTransform (DFT) of the HRTF. For instance, the sound waves aremultiplied with a specific period signal, such as a square signal knownas the Opening. Consider an example in which a sound card includes oneor more digital to analog converters (DACs) that implement a soundconversion algorithm to place sounds at locations around the listener.One or more operational amplifiers (op-amps) transform an output currentfrom the DACs into a drive voltage provided to an amplifier andspeakers.

Sound waves can thus be captured, processed, and altered with HRTFs tochange sound properties before being provided to a listener. Uponhearing the artificially altered sound wave, the listener will believethat the sound originates from a location different than the reallocation.

Example embodiments include two-channel and multi-channel structures toachieve sound localization. In a two-channel structure, digital signalprocessing (DSP) provides sound to a listener through two speakers orearpieces, and in a multi-channel structure, two or more speakers areplaced around and/or near a listener. In the two-channel structure,impulse response filters are characterized according to the HRIRs. TheseHRIRs can be generic (or general) HRIRs or user-specific (or customizedor individualized) HRIRs. Generic HRIRs can be obtained from a dummy ormanikin head with microphones, created or generated from a computermodel, or obtained from a population sample (e.g., a database of HRIRsof individuals used to represent a general population of listeners).User-specific HRIRs can be obtained from measurements of the individuallistener (e.g., providing microphones in ears of the individual,calculating HRIRs from a size and shape of a head, ears, etc. of theindividual).

Furthermore, HRIRs can be obtained from a combination of generic anduser-specific techniques. Consider an example in which initial HRIRs areretrieved from a database of a user having similar facial features andthen adjustments are made to the HRIRs based on measured responses ofthe individual to sound localizations. Consider another example in whichHRIRs are obtained from a database for various measured azimuth andelevation angles. HRIRs for non-measured angles (i.e., those anglesbetween the measured azimuth and elevation angles) can be actuallymeasured or interpolated (e.g., using an HRIR interpolation algorithm,such as a bilinear interpolation model, a triangular interpolationmodel, spherical splines filtering model, a weighted-average model, or aspectral interpolation model). For instance, once the HRIRs areretrieved, measurements from the listener are made over days and/orweeks to provide missing HRIRs to the set of HRIRs retrieved from thedatabase. As time proceeds, more and more HRIRs are added that provide amore accurate mapping of customized HRIRs to the listener.

FIG. 16 is an electronic system 1600 that includes users and electronicdevices at different geographical locations 1610A-1610G and one or moreservers 1620 in communication with each other through one or morenetworks 1630. Geographic location 1610A shows a speaking person 1640Acommunicating through a smartphone 1650A. Geographic location 1610Bshows a speaking person 1640B communicating to a dummy head 1650B withmicrophones as earpieces. Geographic location 1610C shows a listeningperson 1640C hearing sounds from a person on a wearable electronicdevice 1650C. Sounds from this person are localized at a soundlocalization point 1660C at a chair. Geographic location 1610D shows aspeaking person 1640D communicating through a notebook computer 1650D.Geographic location 1610E shows a listening person 1640E hearing soundsfrom a third party through speakers 1650E. Sounds from the third partyare localized at a sound localization point 1660E that occurs in frontof the listening person 1640E. Geographic location 1610F shows a person1640F hearing sounds through and speaking sounds to a wearableelectronic device 1650F. Geographic location 1610G shows a listeningperson 1640G hearing sounds from a third party on a wearable electronicdevice 1650G while the listening person walks. Sounds from the thirdparty are localized at a sound localization point 1660G that occurs infront of the listening person.

FIG. 17 is an electronic system 1700 that includes a listener 1710wearing a wearable electronic device 1720 that communicates with one ormore servers 1730 through one or more networks 1740. The listener 1710is initially located in room 1, and speakers in the wearable electronicdevice 1720 provide sound to the listener. Sound from the wearableelectronic device 1720 localizes in front of the listener at a soundlocalization point 1760 that is empty space located in room 1. As thelistener 1710 moves to room 2, the sound localization point 1760 remainsfixed at the location in room 1. Sound that the listener hears changesas a location and a head orientation of the listener also changes. Thelocation and the head orientation of the listener are tracked with thewearable electronic device 1720 so the sound can be adjusted withmovements of the listener and continue to appear to originate from thesound localization point as the listener moves.

Consider an example in which a music band plays a live performance at avenue in New York City. Binaural sounds of the band playing are sold tolisteners that are located in other cities throughout the United States.Listeners can purchase virtual attendance tickets to the performance.These tickets enable a listener to receive sound of the performance inreal-time at a designated sound localization point that represents alocation of a seat or location at the venue. Listener 1710 purchases aticket that provides a virtual front row seat that the listenerlocalizes in room 1 at the sound localization point 1760. Listener 1710receives the sound through speakers in the wearable electronic device1720 as if the listener were seated in the front row at the venue in NewYork City during the live performance. Sound that the listener 1710hears automatically adjusts to compensate for changes to the headorientation and the location of the listener as the listener moves aboutrooms 1 and 2. For example, amplitude and localization cues (e.g., ITDand ILD) change in real-time as the listener 1710 moves from room 1 toroom 2. Further, the wearable electronic device 1720 can provide thelistener with images and/or video that correspond to the band playing atthe venue. For instance, the listener 1710 sees through a display of thewearable electronic device 1720 a real-time image of the band from afront row seat at the venue corresponding to the ticket purchased.

Consider an example in which a sound localization point is located inone room with a listener, and the listener then moves into an adjacentroom and closes a door between the two rooms. A reduction of sound canbe calculated between the two rooms or for virtual rooms in which thelistener appears to move from one room to another room according to thefollowing equation:

SPL(Receiving Room)=SPL(Source Room)−STL−10 log(SA/A),

where SPL (Receiving Room) is the sound pressure level in the receivingroom, SPL (Source Room) is the sound pressure level in the source room,STL is the sound transmission loss of the wall between the two rooms, SAis the sound absorption in the receiving room, and A is the surface areaof the wall between the two rooms.

FIG. 18 is an electronic system 1800 that includes a handheld portableelectronic device (HPED) 1805 of a listener 1810 and a wearableelectronic device 1815 of a speaker 1820 that communicate during anelectronic call over one or more servers 1830 and one or more networks1840. The wearable electronic device 1815 of the speaker 1820 capturesbinaural sound, and the HPED 1805 provides this sound to the listenersuch that the listener localizes a voice of the speaker 1820 to a soundlocalization point 1850. The HPED 1805 and the wearable electronicdevice 1815 can include position and orientation tracking systems totrack locations and head orientations of the listener 1810 and thespeaker 1820.

The sound localization point 1850 has a size, a shape, and anorientation of a head that emulates a size, a shape, and an orientationof a head of the speaker 1820. When the speaker 1820 moves his head(such as changing location, yaw, pitch, or roll), then a head of thesound localization point 1850 simultaneously changes to emulate or copythis movement. A direction or source of the sound from the soundlocalization point emulates sound from the mouth of the speaker 1820.For instance, if the speaker 1820 rotates his head and mouth twentydegrees (20°) left, then the head and mouth of the virtual head of thesound localization point 1850 contemporaneously rotates twenty degrees(20°) left. This rotation changes the sound that the listener hears eventhough the listener may be hearing the sound through headphones, anearpiece, or speakers that are not actually located at the soundlocalization point 1850.

When the listener 1810 moves his head with respect to the soundlocalization point 1850 (such as changing location, yaw, pitch, orroll), then adjustments are simultaneously made to the sound of thevoice of the speaker to compensate for these movements. Theseadjustments change the sound so the sound that the listener hearsemulates the sound that the listener would hear if the speaker werephysically present at the sound localization point 1850. For instance,the listener 1810 continues to hear the voice of the speaker 1820 at thesound localization point as the listener moves from location 1 in theroom 1860 to location 2 in the room 1860.

The sound localization point 1850 can also represent a location wheresound of the listener is captured with the electronic device 1805. Inother words, the sound localization point 1850 can also include avirtual recording point (VRP) or a virtual microphone point (VMP).Microphones in or associated with the electronic device 1805 capturespoken sound from the listener 1810 (e.g., capture the sound at the headof the listener or at the body of the electronic device). This sound,however, is adjusted so it sounds to the speaker 1820 as if it werecaptured at another location (such as the virtual microphone point that,in this instance, is the sound localization point 1850). As such, soundthat the speaker 1820 hears changes in real-time to compensate formovements of the listener 1810 as the listener talks and moves withrespect to the sound localization point 1850 since this point is also avirtual microphone point. For example, as the listener 1810 moves fromlocation 1 to location 2, an amplitude of the sound provided to thespeaker 1820 decreases since a distance of the listener 1810 from thesound localization point 1850 increases.

FIG. 19 is an electronic system 1900 that includes a wearable electronicdevice (WED) 1910 of an individual 1920 that communicates with one ormore servers 1930 through one or more networks 1940 while the individual1920 is located outdoors 1950. A sound localization point 1960 existsnear a tree 1970.

The sound localization point 1960 represents a location to where theindividual 1920 localizes sound received through the wearable electronicdevice 1910. Sounds that transmit through the wearable electronic device1910 appear to the individual 1920 to originate at the soundlocalization point 1960. For instance, a voice of a third personwirelessly transmits to the wearable electronic device 1910 over theInternet or an outdoor wireless network.

FIG. 20 is an electronic system 2000 that includes a wearable electronicdevice (WED) 2005 of a first person or speaker 2010 and a wearableelectronic device (WED) 2015 of a second person or listener 2020 thatcommunicate during an electronic call over one or more servers 2030 andone or more networks 2040. The wearable electronic device 2005 of thespeaker 2010 captures binaural sound and transmits sound to the listener2020 who localizes the sound at a sound localization point 2050 locatedin a room 2055. The wearable electronic device 2015 of the listener 2020captures binaural sound and transmits sound to the speaker 2010 wholocalizes the sound at a sound localization point 2060 located in a room2065 that is remote from the room 2055. A voice of the speaker 2010localizes to the sound localization point 2050 for the listener 2020,and a voice of the listener 2020 localizes to the sound localizationpoint 2060 for the speaker. The sound localization point 2060 localizesto an empty chair 2070 located in room 2065.

The sound localization point 2050 tracks or follows movements inreal-time of the speaker 2010. When the speaker 2010 changes his headorientation or moves his body, a head orientation or location of thesound localization point 2050 simultaneously moves to emulate andcoincide with movements of the speaker 2010. For example, when thespeaker 2010 moves to his left (as shown in room 2065), the soundlocalization point 2050 moves with an equal distance and an equaldirection in room 2055. For instance, when the speaker 2010 rotates andtilts his head fifteen degrees (15°), then the virtual head thatrepresents the sound localization point 2050 also rotates and tiltsfifteen degrees (15°) in a same direction. These movements change thesound that the listener 2020 hears the speaker 2010 speaking during atelephone call.

For the speaker 2010, a voice of the listener 2020 originates from thechair 2070 in a manner that simulates the listener 2020 sitting in thechair even though the chair is physically empty and no sound actuallyoriginates from the chair. The sound that the speaker 2010 hearsoriginates from the wearable electronic device 2005.

For the listener 2020, a voice of the speaker 2010 originates from thesound localization point 2050 that can exist in empty space in room 2055(such as existing at a single point in space or an area or volume inempty space or occupied space). This sound localization point 2050 canappear to the listener 2020 as a virtual image of the speaker 2010. Forexample, the wearable electronic device 2015 is a pair of electronicglasses with a display that provides an image or video of the speaker2010 in a field of view 2080 of the listener 2020. This image representsthe sound localization point 2050 so the listener 2020 can see the soundlocalization point 2050 as it moves in the room 2055.

FIG. 21 is an electronic system 2100 that includes a handheld portableelectronic device (HPED) 2105 of a first person 2110 and a wearableelectronic device (WED) 2115 of a second person 2120 that communicateduring an electronic call using one or more servers 2130 and one or morenetworks 2140. The HPED 2105 of the first person 2110 captures sound andprovides this sound to the second person 2120 who localizes the sound ata sound localization point (SLP) 2150 located at a geographical location2155. The WED 2115 of the second person 2120 captures sound using alaser microphone and provides this sound to the first person 2110 wholocalizes the sound at a sound localization point (SLP) 2160 located atanother geographical location 2165 that is remote from geographicallocation 2155. A voice of the first person 2110 localizes to the soundlocalization point 2150, and a voice of the second person 2120 localizesto the sound localization point 2160.

A sound localization point can also be a virtual recording point (VRP)or a virtual microphone point (VMP) that is a virtual location wheresound is captured or recorded. Sound is captured or recorded with one ormore electronic microphones at a first geographical location or firstpoint and processed so the sound appears to be captured or recorded at asecond geographical location or second point that is the virtual point.For example, the first person 2110 holds an HPED 2105 that captures,records, and transmits sound (such as a voice of the first person). TheHPED 2105 captures, records, and transmits this sound at or near thebody of the first person 2110 since the first person holds the HPED inhis hand or wears it on his body. Properties of this sound, however, arechanged so that the sound appears to have been captured at a virtualmicrophone point (VMP) 2160 that is located with the SLP and away fromthe first person 2110. For instance, the SLP and VMP are located severalfeet in front of the first person as shown at location 2165. The secondperson 2120 does not hear or localize the voice of the first person 2110as being captured at the HPED 2105, but instead hears or localizes thesound as being captured at the VMP that is a location away from thefirst person.

The second person 2120 wears a WED 2115 that captures, records, andtransmits sound (such as a voice of the second person). The WED 2115captures, records, and transmits this sound at the head of the secondperson 2120 since the second person wears the WED (such as wearing apair of electronic glasses). Properties of this sound, however, arechanged so that the sound appears to have been captured at a virtualmicrophone point (VMP) 2150 that is located with the SLP and away fromthe second person 2120. For instance, the SLP and VMP are locatedseveral feet in front of the second person as shown at location 2155.The first person 2110 does not hear or localize the voice of the secondperson 2120 as being captured at the WED 2115, but instead hears orlocalizes the sound as being captured at the location away from thesecond person.

Sound can also be captured using a physical method to measure the soundimpulses at a remote point, such as using a laser microphone or a devicethat uses a laser beam and smoke or vapor to detect sound vibrations inair. For example, the second person 2120 wears the WED 2115 thatcaptures, records, and transmits sound (such as the voice of the secondperson). The WED 2115 records and transmits this sound at the head ofthe second person 2120 since the second person wears the WED (such aswearing a pair of electronic glasses with a laser microphone). Sound iscaptured not at the location of the WED 2115, but at the SLP and VMP2150 since a laser microphone 2117 is trained on a surface or on smokeor vapor in air at the SLP and VMP located away from the second person.For instance, the SLP and VMP are located several feet in front of thesecond person. As such, the first person 2110 does not hear or localizethe voice of the second person 2120 as being captured at the WED 2115,but instead hears or localizes the sound as it was detected at thelocation 2150 away from the second person.

The VMP and the SLP can be located at a same point or area or located atdifferent points or areas. For example during an electronic telephonecall between a first person and a second person, the first personlocalizes sound from the second person at a sound localization pointthat is eight feet directly in front of a head of the first person. AVMP for the first person, however, is located three feet in front of thefirst person. In this instance, the first person hears the second personas being eight feet in front of the first person, but the second personhears the first person as being three feet in front of the secondperson.

A listening person, a speaking person, another person, and an electronicdevice can establish locations for the VMP and SLP. Conflicts betweenlocations can be resolved according to established rules, defaults, orhierarchies. For example during a telephone call, a listening person haspriority to establish a location of a SLP for a voice of the talkingperson.

Consider an example in which John telephones Paul. An electronic deviceof John establishes a sound localization point for the voice of Paul tobe five feet in front of John and a virtual microphone point for therecording of the voice of John to be five feet in front of John. Theelectronic device of John sends the locations of the SLP and the VMP tothe electronic device of Paul. These two electronic devices handshakeand agree on the SLP and VMP locations.

An electronic device tracks or follows movements in real-time of thespeaker or sound source with respect to the virtual microphone point.When the speaker changes his head orientation or moves his body, thesound is adjusted to compensate for these movements. For example, whenthe speaker moves away from the virtual microphone point, an amplitudeof the sound reduces since a distance between the speaker and thevirtual microphone point increased. Further, an ITD and an ILD of thesound change in response to movements of the head and body of thespeaker in order to emulate sound that real microphones would capture ifthey were located at the virtual microphone point.

FIG. 21 shows the first person 2110 at location 2165 moving fromlocation 1 to location 2. In response to this movement, the SLP and VMP2150 of the first person move an equivalent direction and distance atlocation 2155. Further, the second person 2120 at location 2155 movesfrom location 3 to location 4. In response to this movement, the SLP andVMP 2160 of the second person move an equivalent direction and distanceat location 2165.

FIG. 22 is an electronic system 2200 that includes a wearable electronicdevice (WED) 2205 of a speaker 2210 at a first location 2265 and acomputer 2215 in communication with speakers 2217 near a listener 2220at a second location 2275 that communicate during an electronic callusing one or more servers 2230 and one or more networks 2240. The WED2205 captures sound at two microphones located in or near ears of thefirst person 2210. The sound is adjusted or changed so that the soundappears to be captured at a virtual microphone point 2250 that islocated several feet in front of the speaker 2210. This virtualmicrophone point includes two virtual microphones 2255 located on avirtual dummy head of the virtual microphone point 2250. The computer2215 and speakers 2217 present and record the sound such that thelistener 2220 localizes the sound at a sound localization point 2260that also represents the virtual microphone point.

Consider an example in which a distance between the speaker 2210 and thevirtual microphone point 2250 is equivalent to a distance between thelistener 2220 and the sound localization point 2260. When the speaker2210 moves with respect to the virtual microphone point 2250, the soundlocalization point 2260 simultaneously moves with equivalent speed anddirection with respect to the listener 2220.

FIG. 23 is an electronic system 2300 that includes a computer system2310 at a first location 2315 that communicates with a remote computersystem 2320 at a second location 2325 and a remote computer system 2330at a third location 2335 via one or more servers 2340 and one or morenetworks 2350.

The first location 2315 includes a first user 2360, a second user 2362,and a third user 2364 seated at a conference table 2370. The secondlocation 2325 is remote from the first location 2315 and the thirdlocation 2335 and includes a fourth user 2366. The third location 2335is remote from the first location 2315 and the second location 2325 andincludes a fifth user 2368.

The computer system 2310 at the first location 2315 initiates aconference call with the computer system 2320 at the second location2325 and automatically determines a location of a sound localizationpoint 2380 at the table 2370 for a voice of the fourth user 2366. Duringthe conference call, another participant (i.e., the fifth user 2368)requests to join the call. The computer system 2310 at the firstlocation 2315 communicates with the computer system 2330 at the thirdlocation 2335 and automatically determines a location of a soundlocalization point 2390 at the table 2370 for a voice of the fifth user2368. The determination of where to place the sound localization pointsof the participants is based on determining one or more factorsincluding, but not limited to, available or empty space around thetable, a number of participants in the conference call, identities ofparticipants in the conference call, empty seats or chairs at the table,a location of one or more of the participants, a size and/or shape of aroom in which one or more of the participants are located, an age orrank or title of a participant, a previous location where a participantsat around the table, etc.

Consider an example in which the computer system identifies the fourthuser 2366 as John Smith, and positions John at a head of the table 2370since John is a president of the company hosting the conference call.Consider an example in which the computer system identifies an emptyand/or occupied space and calculates distances between objects, people,SLPs, and/or VMPs at the conference table. The system determines thatthe fourth user 2366 should be situated at an end of the table soparticipants are evenly spaced around the table 2370. Consider anexample in which the computer system determines locations of theparticipants around the table during prior conference calls and placesthe fourth user 2366 at the end of the table since this is where thefourth user sat on two previous conference calls while at location 2315.Consider an example in which the table has five chairs with three ofthese chairs being occupied by a real person (i.e., first user 2360,second user 2362, and third user 2364) and one chair being occupied by asound localization point 2380 of a remote person (i.e., fourth user2366). Based on this information, the computer system elects to placethe sound localization point 2390 of the fifth user 2368 at the emptychair.

During the conference call, the first user 2360, the second user 2362,and the third user 2364 each localize a voice of the fourth user 2366 atthe sound localization point 2380. Further, each of the first, second,and third users localize a voice of the fifth user 2368 at the soundlocalization point 2390. Adjustments are made to the sound for each ofthese users since they are located at different locations around thetable with respect to the sound localization points. These adjustmentsinclude, but are not limited to, calculations for and changes to ITDs,ILDs, HRTFs, attenuation, reverberations, and other aspects of sounddiscussed herein. Further, these adjustments can occur based onmovements to head orientation and location for each user. For instance,sound that the first user 2360 hears from the fourth user 2366 and thefifth user 2368 changes as the first user rotates his head toward thefifth user 2368 since this rotation changes a head orientation of thefirst user with respect to the sound localization point 2380 of thefourth user 2366 and the sound localization point 2390 of the fifth user2368.

Consider an example in which the second user 2362 is speaking to andlistening to the four others (2366 localized at 2380, 2360, 2364, and2368 localized at 2390). In this example, however, the others are notpeople but computer programs with interactive audio input/outputinterfaces. Second user 2362 can hear the progress announced for process2366 on his left, and he can pause, halt, and otherwise control theprocess by voice control, directing his voice to 2380, and likewiserespectively monitoring and controlling each of the four processes bylistening in their direction and speaking the voice commands back to theSLP of each. Each audio window/process could perceive when it was theone being addressed by the user 2362 by comparing the sound pressurereceived relative to that received at the other three process/windowpoints and/or by monitoring the head orientation of user 2362. Computeruser 2362 can hear each of his programs running in a different spot onhis large desk. Further, this user can move the SLPs of a window/processusing, for example, a voice command, a mouse, a head or other bodygesture, or other method while he is using them or while he is on anelectronic call to the person designated at the SLP. Further yet, thisuser can arrange the SLPs of the window/process in any order and/or moveany of them to the foreground (such as bringing the associated SLPtoward him to make the sound louder), moving any of them to thebackground (such as bringing the SLP away from him to make the soundsofter), and moving any of them to increase or decrease priority oraccess to resources (such as computer processing power, resolution,bandwidth, etc.). Even if the user has a single set of audio speakers,the audio from a movie being watched on screen 4 would be perceived tocome from screen 4. The audio from a game being played on screen 2 wouldbe perceived to come from screen 2. A change to any SLP position canalert the corresponding user and trigger an equivalent SLP positionchange. For example, during the call the first user adjusts the SLP 2390to be directly in front of him on the table. In response to thismovement, the fifth user 2368 is alerted of the change and is aware thathe has been placed at the position designated by the first user.

FIG. 24 is an electronic system 2400 that includes a computer system2410 at a first location 2415 that communicates with a remote wearableelectronic device 2420 at a second location 2425 via one or more servers2430 and one or more networks 2440. Location 2415 includes a room with aspeaker 2450, a table 2452, a chair 2454, a window 2456, and otherfurnishings. Location 2415 also includes a sound localization point(SLP) and a virtual microphone point (VMP) 2470. The SLP and VMP aresituated at, on, or above the empty chair 2454 that represents alocation of a listener 2460 if the listener were present at the location2415 with the speaker 2450. Location 2425 includes the listener 2460that wears the wearable electronic device 2420.

If the listener 2460 were seated at the chair 2454 in the room at theSLP and VMP 2470, then sound impulses from the speaker 2450 would travelfrom the mouth of the speaker to the ears of the listener seated at thechair. These sound impulses, however, would be affected by a physicalenvironment of the room, such as a size and a shape of the room (shownwith lines 2472), objects in the room (e.g., the table 2452, the chair2454, the window 2456, etc.), ambient conditions in the room, materialsthat form the walls, ceiling, and floors of the room, etc. Further, anorientation and location of the head of the speaker 2450 would alsoaffect how these sound impulses reached the listener (such as how soundis transmitted, reflected, and absorbed).

One way to capture changes to the sound based on the physicalenvironment of the room would be to place microphones on the chair 2454where ears of a listener would be situated. Another way is to simulateor calculate these changes and adjust the sound so the listener hearsthe sound as if he were seated on the chair. These calculations can bemade by knowing the physical environment of the room (such as knowingthe size and shape of the room, knowing the composition and location ofobjects, knowing the location and orientation of the speaker, knowingthe location of the VMP, knowing ambient conditions in the room, knowingmaterials from which the room is composed to determine a soundabsorption coefficient for the material, etc.).

Consider an example in which microphones on a wearable electronic deviceon the speaker 2450 capture binaural sound as it leaves the mouth of thespeaker. The computer system 2410 tracks a location and orientation of ahead of the speaker and also retrieves or determines informationrelating to the physical environment of the room at location 2415. Basedon this information, adjustments to the captured binaural sound are madeso the sound appears to have been recorded at the chair 2454 where theVMP is located. The adjusted sound is provided to the listener 2460 atthe remote location 2425. The adjusted sound includes or carries cues asto its origination, including the physical environment of the room wherethe speaker 2450 is located. These cues provide a three dimensional (3D)audial picture to the listener, and this audial picture includes thephysical environment of the room of the speaker (e.g., the audialpicture being shown as dashed lines of the speaker 2450′, the table2452′, the chair 2454′, the window 2456′, size and shape of the room2472′ in which the speaker is located, and other objects shown withdashed lines).

FIG. 25 is an electronic system 2500 that includes a wearable electronicdevice 2510 at a first location 2515 (shown with a speaker 2520 in anempty room) and a wearable electronic device 2530 at a second location2535 (shown with a listener 2540 in an empty room) that communicate viaone or more servers 2550 and one or more networks 2560. Location 2515also includes a virtual microphone point (VMP) 2570, and location 2535includes a sound localization point 2575 where the listener 2540localizes sounds and a voice from the speaker 2520.

Sound can be adjusted to include audial cues for an artificial 3Dphysical environment. These cues include changes to the sound to adjustfor ambient conditions and physical objects that are not present at thelocation where the sound is captured. For example, the wearableelectronic device 2510 captures binaural sound in an empty room from thespeaker 2520. If this sound were transmitted to the wearable electronicdevice 2530, then the listener 2540 would hear a voice of the speaker2520 as originating at the head of the listener 2540 since the sound wascaptured at the head of the speaker. The sound can be adjusted (such aschanging ITDs, ILDs, and HRTFs) to move a localization point of thissound for the listener 2540 to the sound localization point 2575 that islocated in front of the listener. The sound can be further adjusted toadd an artificial environment where the speaker is located. Theseadjustments extend beyond adding artificial sound, such as backgroundnoise.

Adjustments to the sound include adding an artificial or virtualphysical environment where the sound was captured. For example, thesound is adjusted to change the location of the speaker from being in anempty room to being outside on a rainy day with physical objects nearby.These adjustments are shown at location 2535 with dashed lines of anartificial physical environment that includes clouds and a thunderstorm2580, mountains or hilly terrain 2582, a nearby automobile 2584, and anairplane 2586. These physical objects, if present at location 2515,would affect how a voice of the speaker 2520 propagated to the virtualmicrophone point 2570. The sound is adjusted to simulate the existenceof these objects so the listener perceives or hears an artificialphysical environment for the speaker.

Example embodiments include electronic devices that capture binauralsound (such as an HPED or smartphone that captures binaural sound from atalking person and delivers binaural sound to a listening person) andnon-binaural sound (such as calls originating from an electronic devicewith monophonic or stereophonic sound).

Consider an example in which a listener wears an electronic deviceduring a telephone call with a first speaker who is using a monophonicmobile phone. The listener is located in a quiet place, and the firstspeaker is in a noisy place, so the sound is localized to suit theatmosphere of the listener by filtering out the background noise. A SLPis designated to the right of the listener by adjusting an ITD by about0.7 ms and by adjusting the ILD. At a later time in the call, thelistener receives another call from a second speaker who is using anantique monophonic land-line phone. The listener admits the secondspeaker into the call with the first speaker so that all three can speakand hear each other. Static exists on the line with the second caller sothe call is localized to match a static-free call environment of thelistener and first speaker. Also, a second SLP is designated to the leftof the Listener using the ITD and ILD as with the first speaker. So thelistener perceives the first caller off to the right side of his faceand the second caller to the left side of his face. At a later time inthe call the listener receives another call from a third speaker who isusing a Voice over Internet Protocol (VoIP) program running on anotebook computer equipped with one microphone. The listener admits thethird speaker into the call with the listener and the first speaker andthe second speaker. A third SLP is designated for the third speaker tobe directly between the ears of the listener at a point inside his head.Now the listener perceives the first caller off to the right side of hisface, the second caller to the left side of his face, and the thirdcaller between the first and second callers. At a later time in thecall, the listener receives another call from a fourth speaker. Thelistener admits the fourth speaker into the call with the listener andthe other three speakers. A fourth SLP is designated for the fourthspeaker at a same location with the first SLP with a same or similar ITDas the sound from the first speaker. In order to spatially distinguishthe fourth speaker from the first speaker and the other speakers in thecall, the ITD is gradually changed from 0.7 ms to 0 to 0.7 ms and thenslowly back to 0.7 ms, repeatedly so that the listener perceives thefourth speaker to be moving slowly back and forth between the SLP of thefirst speaker and the SLP of the second speaker and back to the first.The ITD is incremented or decremented during times or moments when thefourth speaker is making sound, and not when he is silent. As such,whenever the fourth speaker begins to speak after a pause, he isperceived by the listener to be at the same place he was last perceivedby the listener, and the listener will not perceive the fourth speakersuddenly at a SLP where he was not previously present.

Consider an example in which a listener and a talking person wear or usean electronic device that captures, transmits, and/or provides binauralsound during a telephone call. In the first part of the call, a VMP atthe location of the speaker is designated to be at the point of theactual physical microphones being worn by the speaker (e.g., being atthe ears of the speaker). As such, various sounds in the environment ofthe speaker are perceived by the listener to emanate from locationsrelative to the ears of the listener, and the SLP of the speaker's voiceis perceived by the listener as approximately at the point of the mouthof the listener. Later in the call it is determined that the vocal partof the sound being sent by the speaker should be moved to a SLP off tothe right side of the face of the listener. By way of example, the vocalpart of the sound captured by the device worn by the speaker can beidentified by the intersection of the set of frequencies associated withvoice and with amplitudes and sound pressures matching those that likelyemanated from the oral cavity a few inches away from the microphones,sounds matching a predefined voiceprint of the speaker, soundsassociated with vibrations measured by a sensor mounted on or near theneck, head, or torso of the speaker, and sounds that are measured to beof near equal amplitude in both the left and right microphone sourcesindicating a high probability that they originated from the mouth of thespeaker or directly ahead at zero degrees azimuth from the face of thespeaker. The identified vocal component of the sound captured from thespeaker is removed from the sound sent directly to the headphones of thelistener, and the SLP of the vocal component is designated to the rightside of the face of the listener using an ITD and an ILD. At this time,the listener's voice is also designated at a SLP to the left of the faceof the speaker, and both the speaker and the listener have theperception that they are positioned side-by-side with the listener tothe left of the speaker.

Consider an example in which a speaker wears headphones that capture andplay binaural sound and include two microphones (e.g., each ear includesa microphone that wirelessly sends and receives through a binauralcapable HPED). A third microphone (such as a noise-canceling microphone)captures a voice of the speaker while the two binaural microphones atthe ears of the speaker capture and record sound of the environment. Thevoice signal captured by the third microphone is then used to assist inisolating and removing the voice component captured by the ear-mountedmicrophones, and also as the voice signal transmitted to the listenerthat may also include distance cues according the distance between thevoice reference microphone and the speaker. A voice SLP can bedesignated as above using ITD and ILD. For example, the speaker candesignate as a voice reference microphone a dedicated microphone mountedat or near the head of the speaker. A speaker can also designate themicrophone in an HPED as the voice reference microphone. In this way,the speaker designates the distance of the VMP by way of designating thedistance of the voice reference microphone from himself. The directionalaspect of the voice SLP may be adjusted by ITD and ILD.

Isolating the vocal component of the sound captured by the speakerallows a vocal SLP to be designated to the left or to the right of thelistener in the listener's frame of reference. Further, distance cuescan be perceived by using a voice-sensitive microphone in an availableHPED as the voice reference microphone set at a distance from thespeaker. Further yet, a speaker can use four microphones to provide aclear voice signal and an improved distance-localized voice signal tothe listener. A third microphone or voice reference microphone mountednear the head of the speaker aids to isolate and remove the vocal partof the sounds captured by the first and second microphones mounted atthe left and right ears of the speaker as described herein. In thisexample, sound captured at the third microphone is not sent to thelistener. Instead, a fourth microphone (such as a microphone in an HPEDof a speaker) is designated to capture the voice of the speaker,including cues as to the distance between the speaker and the positionof the fourth microphone. The vocal sound captured from the thirdmicrophone is used to enhance the sound captured by the fourthmicrophone, to isolate and cancel non-vocal components of sound, and toimprove the clarity of a vocal part of the signal that is ultimatelyprovided to the listener.

FIG. 26 is a computer system or electronic system 2600 that includes acomputer or an electronic device 2602, a computer or electronic device2604, and storage 2606 in communication with each other over one or morenetworks 2608. The storage can include memory or databases with HRTFsand/or HRIRs 2610.

By way of example, a computer and an electronic device include, but arenot limited to, handheld portable electronic devices (HPEDs), wearableelectronic glasses, watches, wearable electronic devices, portableelectronic devices, computing devices, electronic devices with cellularor mobile phone capabilities, digital cameras, desktop computers,servers, portable computers (such as tablet and notebook computers),electronic and computer game consoles, home entertainment systems,handheld audio playing devices (example, handheld devices fordownloading and playing music and videos), personal digital assistants(PDAs), combinations of these devices, devices with a processor orprocessing unit and a memory, and other portable and non-portableelectronic devices and systems.

Electronic device 2602 includes one or more components of computerreadable medium (CRM) or memory 2620, one or more displays 2622, aprocessing unit 2624, one or more interfaces 2626 (such as a networkinterface, a graphical user interface, a natural language userinterface, a natural user interface, a reality user interface, a kineticuser interface, touchless user interface, an augmented reality userinterface, and/or an interface that combines reality and virtuality), acamera 2628, one or more sensors 2630 (such as micro-electro-mechanicalsystems sensor, a biometric sensor, an optical sensor, radio-frequencyidentification sensor, a global positioning satellite (GPS) sensor, asolid state compass, gyroscope, magnetometer, and/or an accelerometer),a sound localization system 2632 (such as a system that localizes sound,adjusts sound, predicts or extrapolates characteristics of sound,detects sound impulses using light (such as a fiber optic microphone ora laser microphone), and/or executes one or more methods discussedherein), a virtual microphone system 2634 (such as a system thatcaptures sounds, adjusts sound, and/or executes one or more methodsdiscussed herein), a facial recognition system 2636, a head and/or eyetracker 2638, a location or motion tracker 2640, one or more microphones2642, and one or more speakers 2644. The sensors can further includemotion detectors (such as sensors that detect motion with one or more ofinfrared, optics, radio frequency energy, sound, vibration, andmagnetism). By way of example, the location or motion tracker includes,but is not limited to, a wireless electromagnet motion tracker, a systemusing active markers or passive markers, a markerless motion capturesystem, video tracking (e.g. using a camera), a laser, an inertialmotion capture system and/or inertial sensors, facial motion capture, aradio frequency system, an infrared motion capture system, an opticalmotion tracking system, an electronic tagging system, a GPS trackingsystem, and an object recognition system (such as using edge detection).

Electronic device 2604 includes one or more components of computerreadable medium (CRM) or memory 2660, one or more displays 2662, aprocessing unit 2664, one or more interfaces 2666, an object recognizer2668, an ambient condition analyzer 2670, a sound localization system2672 (such as a system that localizes sound, adjusts sound, and/orexecutes one or more methods discussed herein), a virtual microphonesystem 2674 (such as a system that captures sounds, adjusts sound,predicts or extrapolates characteristics of sound, detects soundimpulses using light, and/or executes one or more methods discussedherein), and an imagery system 2676 (such as an optical projectionsystem, a virtual image display system, virtual augmented realitysystem, and/or a spatial augmented reality system). By way of example,the virtual augmented reality system uses one or more of imageregistration, computer vision, and/or video tracking to supplementand/or change real objects and/or a view of the physical, real world.

FIG. 26 shows example electronic devices with various components. One ormore of these components can be distributed or included in variouselectronic devices, such as some components being included in an HPED,some components being included in a server, some components beingincluded in storage accessible over the Internet, some components beingin an imagery system, some components being in wearable electronicdevices, and some components being in various different electronicdevices that are spread across a network or a cloud, etc.

The processor unit includes a processor (such as a central processingunit, CPU, microprocessor, application-specific integrated circuit(ASIC), etc.) for controlling the overall operation of memory (such asrandom access memory (RAM) for temporary data storage, read only memory(ROM) for permanent data storage, and firmware). The processing unitcommunicates with memory and performs operations and tasks thatimplement one or more blocks of the flow diagrams discussed herein. Thememory, for example, stores applications, data, programs, algorithms(including software to implement or assist in implementing exampleembodiments) and other data.

Blocks and/or methods discussed herein can be executed and/or made by auser, a user agent of a user, a software application, an electronicdevice, a computer, a computer system, and/or an intelligent personalassistant.

As used herein, “empty space” is a point or a location that is notfilled or occupied. For example, a location where a human would sit inan empty chair includes an empty space since this location is not filledor occupied.

As used herein, “sound localization” is a process of determining alocation, an origin, or a place of emanation of sound.

As used herein, “sound localization point” is a particular location orposition that is determined to be a location, an origin, or a place ofemanation of sound.

As used herein, “virtual microphone point” is a virtual location orvirtual position where sound is captured, recorded, or monitored.

As used herein, a “wearable electronic device” is a portable electronicdevice that is worn on or attached to a person. Examples of such devicesinclude, but are not limited to, electronic watches, electronicnecklaces, electronic clothing, head-mounted displays, electroniceyeglasses or eye wear (such as glasses in which augmented realityimagery is projected through or reflected off a surface of a lens),electronic contact lenses (such as bionic contact lenses that enableaugmented reality imagery), an eyetap, handheld displays that affix to ahand or wrist or arm (such as a handheld display with augmented realityimagery), and HPEDs that attach to or affix to a person.

In some example embodiments, the methods illustrated herein and data andinstructions associated therewith are stored in respective storagedevices, which are implemented as computer-readable and/ormachine-readable storage media, physical or tangible media, and/ornon-transitory storage media. These storage media include differentforms of memory including semiconductor memory devices such as DRAM, orSRAM, Erasable and Programmable Read-Only Memories (EPROMs),Electrically Erasable and Programmable Read-Only Memories (EEPROMs) andflash memories; magnetic disks such as fixed, floppy and removabledisks; other magnetic media including tape; optical media such asCompact Disks (CDs) or Digital Versatile Disks (DVDs). Note that theinstructions of the software discussed above can be provided oncomputer-readable or machine-readable storage medium, or alternatively,can be provided on multiple computer-readable or machine-readablestorage media distributed in a large system having possibly pluralnodes. Such computer-readable or machine-readable medium or media is(are) considered to be part of an article (or article of manufacture).An article or article of manufacture can refer to any manufacturedsingle component or multiple components.

Method blocks discussed herein can be automated and executed by acomputer, computer system, user agent, and/or electronic device. Theterm “automated” means controlled operation of an apparatus, system,and/or process using computers and/or mechanical/electrical deviceswithout the necessity of human intervention, observation, effort, and/ordecision.

The methods in accordance with example embodiments are provided asexamples, and examples from one method should not be construed to limitexamples from another method. Further, methods discussed withindifferent figures can be added to or exchanged with methods in otherfigures. Further yet, specific numerical data values (such as specificquantities, numbers, categories, etc.) or other specific informationshould be interpreted as illustrative for discussing exampleembodiments. Such specific information is not provided to limit exampleembodiments.

1.-20. (canceled)
 21. A method executed by a smartphone that provides avoice of a person during a telephone call to a user of the smartphone inbinaural sound, the method comprising: storing, in a memory of thesmartphone, head-related transfer functions (HRTFs) that areuser-specific to an anatomy of the user of the smartphone; receiving, ata network interface of the smartphone and during the telephone callbetween the person and the user, a wireless transmission that includesthe voice of the person in mono sound; processing, with a digital signalprocessor (DSP) in the smartphone, the voice of the person in mono soundwith a pair of the HRTFs to change the voice into the binaural sound sothe voice of the person in the binaural sound externally localizes at asound localization point (SLP) that is in empty space one meter awayfrom a head of the user; tracking, with at least one of anaccelerometer, gyroscope, and magnetometer in the smartphone, headmovements of the head of the user during the telephone call; selecting,with a processor in the smartphone during the telephone call, differentpairs of the HRTFs based on the head movements of the head of the usertracked with the at least one of the accelerometer, the gyroscope, andthe magnetometer; processing, with the DSP in the smartphone, the voiceof the person in mono sound with the different pairs of the HRTFs so thevoice of the person continues to localize at a fixed location at the SLPthat is in empty space one meter away from the head of the user whilethe head of the user moves during the telephone call; and playing,through earphones or headphones in communication with the smartphone,the voice of the person in the binaural sound so the voice of the personcontinues to localize at the fixed location at the SLP that is in emptyspace one meter away from the head of the user while the head of theuser moves during the telephone call.
 22. The method of claim 21,wherein the fixed location at the SLP that is in empty space is above anempty chair in a room where the user is located while the user talks tothe person who is located at another geographical location.
 23. Themethod of claim 21 further comprising: receiving, at a natural languageuser interface of the smartphone during the telephone call, a voicecommand from the user to change the voice of the person from externallylocalizing as the binaural sound to internally localizing as the monosound; and playing, through the earphones or the headphones in wirelesscommunication with the smartphone, the voice of the person in the monosound in response to receiving the voice command during the telephonecall to change the voice of the person from externally localizing as thebinaural sound to internally localizing as the mono sound.
 24. Themethod of claim 21 further comprising: receiving, at a user interface ofthe smartphone during the telephone call, a voice command from the userto move the SLP to another fixed location that is in empty space onemeter away from the head of the user; and playing, through the earphonesor the headphones in wireless communication with the smartphone, thevoice of the person to externally localize to the user at the anotherfixed location that is in empty space one meter away from the head ofthe user in response to receiving the voice command during the telephonecall.
 25. The method of claim 21 further comprising: displaying, with adisplay of the smartphone and at the SLP that is in empty space onemeter away from the head of the user, an image that represents theperson with whom the user is talking during the telephone call; andreceiving, at the smartphone during the telephone call, a command fromthe user to move the SLP and the image to another location that is inempty space one meter away from the head of the user.
 26. The method ofclaim 21, wherein the different pairs of the HRTFs are selected inreal-time as the head of the user moves with respect to the SLP so thevoice of the person continues to localize at the fixed location at theSLP, a loudness of the voice of the person increases as the user movescloser to the SLP, and the loudness of the voice of the person decreasesas the user moves away from the SLP.
 27. The method of claim 21 furthercomprising: designating, with the smartphone, a virtual microphone pointthat to be at the SLP where the voice of the person externally localizesto the user.
 28. The method of claim 21, further comprising: displaying,with a display of the smartphone and on a physical empty chair in frontof the user, an image that represents the person with whom the user istalking during the telephone call, wherein the image that represents theperson exists at the SLP that is in empty space one meter away from thehead of the user.
 29. A non-transitory computer readable storage mediumstoring instructions that a smartphone executes to provide a voice of aperson as binaural sound to a user of the smartphone during a Voice overInternet Protocol (VoIP) call between the user and the person, themethod comprising: retrieving head-related transfer functions (HRTFs)that are customized to the user and that are stored in memory of thesmartphone; processing, with a digital signal processor (DSP) in thesmartphone and during the VoIP call, the voice of the person in monosound with the HRTFs to change the voice from the mono sound into thebinaural sound so the voice of the person externally localizes at asound localization point (SLP) that is in empty space one meter awayfrom a head of the user; tracking, with the smartphone, head movementsof the head of the user with respect to the SLP during the VoIP call;selecting, with the smartphone and based on the head movements withrespect to the SLP during the VoIP call, different ones of the HRTFs toprocess the voice of the person; processing, with the DSP in thesmartphone, the voice of the person in the mono sound with the differentones of the HRTFs to change the voice from the mono sound into thebinaural sound so the voice of the person continues to externallylocalize at the SLP that is in empty space one meter away from the headof the user as the head of the user moves with respect to the SLP duringthe VoIP call; and providing, through earphones or headphones incommunication with the smartphone, the voice of the person in thebinaural sound so the voice of the person continues to externallylocalize at the SLP that is in empty space one meter away from the headof the user as the head of the user moves with respect to the SLP duringthe VoIP call.
 30. The non-transitory computer readable storage mediumstoring instructions of claim 29 that further cause the smartphone toexecute the method comprising: designating the SLP at coordinatelocations received from a smartphone of the person.
 31. Thenon-transitory computer readable storage medium storing instructions ofclaim 29, wherein the SLP is located at a static location in a virtualroom where the user talks to the person, and the voice of the personcontinues to localize to the user from the static location at the SLP asthe user moves in the virtual room with respect to the SLP during theVoIP call.
 32. The non-transitory computer readable storage mediumstoring instructions of claim 29 that further cause the smartphone toexecute the method comprising: displaying, with a display of thesmartphone and during the VoIP call, an image that represents the personat a location of the SLP such that the voice of the person originatesfrom the SLP and the image that represents the person; and moving,during the VoIP call and in response to receiving a command from theuser, the location of the SLP from a left side of the head of the userto a SLP located at a right side of the head of the user that is inempty space one meter away from the head of the user.
 33. Thenon-transitory computer readable storage medium storing instructions ofclaim 29 that further cause the smartphone to execute the methodcomprising: displaying, with a display of the smartphone, an imagerepresenting the person at a location in a computer-generated room thatcorresponds to the SLP so that the voice of the person originates fromthe image representing the person; and maintaining the SLP at a fixedposition in the computer-generated room while the user moves in thecomputer-generated room with respect to the SLP and while the head ofthe user rotates with respect to the SLP.
 34. The non-transitorycomputer readable storage medium storing instructions of claim 29 thatfurther cause the smartphone to execute the method comprising:adjusting, the different ones of the HRTFs processing the voice of theperson, in real-time as the head of the user moves in order to maintainthe SLP at a static location in a physical room of the user.
 35. Thenon-transitory computer readable storage medium storing instructions ofclaim 29 that further cause the smartphone to execute the methodcomprising: capturing, with a camera, a picture of a face of the user;comparing a size and a shape of the face of the user with sizes andshapes of faces of individuals with known HRTFs; determining, based onthe comparing, a match between the size and the shape of the face of theuser with one of the individuals with the known HRTFs; and selecting theHRTFs based on the match between the size and the shape of the face ofthe user with one of the individuals with the known HRTFs.
 36. Thenon-transitory computer readable storage medium storing instructions ofclaim 29 that further cause the smartphone to execute the methodcomprising: designating a virtual microphone point at the SLP;determining, with the smartphone, a distance and a head orientation ofthe user with respect to a location of the virtual microphone point; andincreasing a volume of the voice of the user that the person hears asthe user moves closer to the virtual microphone point.
 37. A smartphonethat provides a voice of a person during a telephone call to a user ofthe smartphone in binaural sound, the smartphone comprising: a memorythat stores head-related transfer functions (HRTFs) that are specific toan anatomy of the user of the smartphone; a network interface thatwirelessly receives the voice of the person in mono sound or stereosound; a digital signal processor (DSP) that processes, during thetelephone call, the voice of the person in the mono sound or the stereosound with the HRTFs to change the voice into the binaural sound so thevoice of the person in the binaural sound externally localizes at asound localization point (SLP) that is in empty space one meter awayfrom a head of the user; one or more of an accelerometer, a gyroscope,and a magnetometer that track head movements of the head of the userwith respect to the SLP during the telephone call; a processor thatcommunicates with the one or more of the accelerometer, the gyroscope,and the magnetometer to select different ones of the HRTFs with whichthe DSP processes with the voice of the person in the mono sound or thestereo sound so the voice of the person in the binaural sound continuesto externally localize at a fixed location at the SLP that is in emptyspace one meter away from the head of the user while the head of theuser moves with respect to the SLP during the telephone call; andprocessing, with the DSP in the smartphone, the voice of the person inthe mono sound or the stereo sound with the different pairs of the HRTFsso the voice of the person continues to externally localize at the fixedlocation at the SLP that is in empty space one meter away from the headof the user while the head of the user moves with respect to the SLPduring the telephone call; and wherein the smartphone provides the voiceof the person to one of earphones or headphones in communication withthe smartphone so the voice of the person continues to externallylocalize at the fixed location at the SLP that is in empty space onemeter away from the head of the user while the head of the user moveswith respect to the SLP during the telephone call.
 38. The smartphone ofclaim 37 further comprising: an interface that receives a voice commandto move the voice of the person from externally localizing at the fixedlocation at the SLP to internally localizing inside the head of the userin the mono sound or the stereo sound.
 39. The smartphone of claim 37further comprising: a display that displays, to the user during thetelephone call, a virtual image of the person at the fixed location atthe SLP that is in empty space one meter away from the head of the user,wherein the voice of the person and the virtual image continue to existat the fixed location at the SLP while the head of the user rotates withrespect to the SLP and the virtual image during the telephone call. 40.The smartphone of claim 37, wherein the smartphone selects a location ofthe SLP based on previous locations of an SLP where the person was withrespect to the user while the user was being tracked.